Belted cases are seen in 6.5 Grendel AR rifles with 22” or 24” barrels. Bolt is unlocking while chamber pressure is too high. It’s called dwell time. Some powders that work ok in a 20” or shorter barrel will not work in the longer barrel.
Late to this thread, but I just went through the same issue even when sizing Hornady cases from Hornady ammo. The issue seems to be the Hornady die is too aggressive a sizer. It is cut even closer to a small base die. My Hornady die is measuring .4350" at the die entry. I also have 6.5 Grendel and the die entry is .4380 to .4385". 6 ARC chambers are SAAMI spec if the .200" dimension is .4426" and a -.002" tolerance is allowed. My chamber is .441" at the .200" dimension (thus it is tighter than minimum), and the case heads start at .438" new and grow about .0005" each firing. The die sizes just below the .200 line and the die is hitting the thick part of the case web which has grown to .441". Therefore the die is trying to reduce the case head material by about .006", and that results in a belt as per the picture. Spring back will result in a case diameter above the belt of about .437". The only cure is to use a different makers die, or hone the Hornady die out to about .4385" . The Hornady is also oversizing the shoulder diameter from .431" down to .4255". Therefore the die will work for converting new 6.5 Grendel brass to 6 ARC, but will fail when sizing the fired brass after about 3 uses. Next step for me is to wait for my LE Wilson die to show up, and just use the Hornady die for converting new brass. I may chuck the die in a lathe and use a boring bar to cut .003 to .004" off the inside to match the LEE die a friend lent me.
This happened to me using a fast burn rate for bullet weight load. Case head was bulged a bit and plowed a belt around the bottom upon resizing. Did not see case head separation signs.
Have been watching your channel for some time now and I have to say that your videos are informative and entertaining. Have learned a ton from watching and have used the information garnered from watching the videos. Keep up the good work.
Well, Ive been re-forming 6.5 Grendel brass, and I ran into this issue. I believe it is from the full length resizing die pushing the brass into a pile at the bottom of the case. I hadn't even fired the brass in my 6mm ARC rifle yet. One other thing to note, is that my ridges are considerably more narrow, and more towards the bottom of the case. Also, I did experience a little of this while resizing real 6mm ARC brass. These were reloads, but they were TAC and CFE223 powder, and not anywhere near max load, rather closer to minimum loads. I just got another batch of once fired 6.5 Grendel brass (40 pieces) and I'm gonna be resizing it this evening. I'll figure out a way to post or send you pictures, if re-forming causes this anomaly. Really appreciate and like these videos, as I am learning a lot more than the 40 years on my own. Thanks Sean!
I just resized a 6.5 Grendel case and noticed a very slight belting line in the exact spot as in Johnny's video. Like you, I also came to the conclusion that it is a result of a slightly over pressured (expanded) case in the full length sizing die.
Soft case heads and too much pressure. (Bolt opening too early) That band is from bolt head support. Its case head swell from. Again. Soft brass & or too Much pressure! I was reading my Gendel handbook an dont ya know this isue is know !! It is a result of the bolt opening too soon!
I just received 1000 once fired 7.62 x39 brass and almost half had that little ring just above the head. I lost 10 out of 500 due to not lubed enough in the neck and shoulder area. I left the bullet expander in the die and it did help. Thank you for the post. 6 ARC brass seems to be impossible to find. I'm gonna size and send them from behind a wall.
First time I ever saw this was on a buddy’s 28” RLGS 6.5 Grendel over 10 years ago. Same load in a 20” RLGS Grendel did not exhibit this symptom. If you have a gas system driven with a higher charge weight, with too much plug dwell time, the bolt will unlock too early. He could actually load the 20” RLGS with higher charge weights and nothing, but the 28” RLGS would produce those “belted magnum” like symptoms.
Same issue, and was due to not lubing case enough when sizing, none occurred after firing. I took all the belted ones and filed off the belt, checking with a case gauge. Work fine now, and I learned to use enough lube!
If memory serves the brass hardness/strength should be in the ballpark of 200 +/- 10 on the Brinell scale. Check hardness to make sure the material has not been annealed.
The PPU ridge/ring is what I see on all European brass (PPU, BELOM, GFL, GECO, NORMA, etc.) that was formed from 7.62x39 and that's because their case head is bigger in diameter compare to American brass including PMC. I commented this on your forming video.
Agreed! Privi Patrisan loaded grendel ammo had a "bad batch" and recall years ago and were blowing brass and locking up guns. You're spot on in your assessment!
I was reading online and some sources say that true 7.62x39 is actually slightly tapered. If so that would explain the ring, especially when using a small base die. If you have some more unaltered 7.62x39 Lapua brass measure the width at the shoulder and then measure the width just above the webbing of the case and see if there are any differences. On the stuff I read it seems like there was some gray area RE: 7.62x39 brass, sort of like the difference between .223 and 5.56. It is conceivable that Lapua has a slight taper (thus causing that ring) whereas other manufacturers don't do that.
7.62x39 is surely tapered. Its even visible. I have reformed 7.62x39 lapua to 6.5 grendel. But the cape capacity was WAY to small to be usefull, 5 grains of water less if i recall correcrly. Thats 10% or even more difference! Makes it impossible to mix with other brass. Lapua and hornady grendel brass is basicly the same, 0.2 grains difference max.
My SPR clone used to do that randomly with once fired LC brass when I was chasing Mk 262 performance. It would do it at low pressure (FPS in the 2500 range), normal pressure, slightly high pressure (2700 tops). All powders, all primers, 2 different sizing dies, mostly 77gr SMKs and CCs. I thought maybe the brass was old machine gun stuff, just bad, so I used some of my own verified once fired stuff, same results. Had a smith take the gun apart and check everything, all in spec. Rainier barrel with a fail zero BCG. We never figured it out, so I just switched to Winchester brass and it never happened again, even with hotter loads. I'm absolutely no help.
I just read about this in Glen Zediker’s book Handloading for Competition (p198 if you have it). He says if the gap between the bolt face and the rear of the chamber is too wide you can end up with this step forming and the rifle isn’t safe to shoot. Others have said it could be over gassed and extracting too soon whilst pressure is too high, which sounds reasonable too. At 2:25 the case in the centre looks like it has a dent from the extractor, which might make sense if the extractor was yanking on the rim before the pressure has dropped. Just my thoughts and I’m certainly not an expert!
I've only converted Star Line and Hornady brass the same way you did here with a standard sizing die then running an expanding mandrel through it to set neck tension and I've had the same results you did here except I don't anneal until after I fire form ... I honestly think using the SB sizing die is pushing brass into places it's not supposed to be and also agree your ejector grove looked squished on the brass you cross sectioned and that also tells me your brass is moving in ways it's not supposed to. It might have something to do with annealing the brass then using the SB sizing die to form it but it's definitely interesting. Great video as always keepem coming brother!!
Just completed my rifle and I read somewhere that Hornady may have some out of spec dies. I went with Lee dies and formed from 6.5 Grendel virgin brass. Fire formed a couple today and didn’t have the belted ring issue you’re having. I’ll gladly order some Lee dies and send them your way if you’re interested. I feel I owe it to you as much as I’ve learned from you! Thanks Shannon!!
When I first saw this and I’m no expert. I instantly thought the shell was ejecting before pressure was released allowing the back to expand out. I originally was thinking it was a chambering flaw, but since it’s not every case that eliminated that idea.
Oddly timely.. I just had a similar event. I was shooting some factory ammo (108 match/105 black) on a new odinworks barrel. My first 10 rounds were on the gas setting that I dialed in on break-in day and I was getting bent necks and that ring. In my case, the ring appeared to be in a semicircle around half of the case. I spent a few rounds turning down the gas and the neck issue and rings went away after that.
This appears to be the classic symptoms of gas guns of either the dwell timing is too short before bolt starts unlocking from battery or the gas port pressure (not overall case pressure) is too high and unlocking the bolt too quickly after the correct dwell delay. If it was a dwell time issue, that would likely happen on nearly all compatible bullet weights and powders that are safe full power loads. If it is a port pressure issue, that would mainly be influenced by powder & bullet combo. An adjustable gas block would just add a variable to the mix. Probably a good diagnostic step would be run the fastest compatible powder that is listed on published reloading data for a given bullet weight and get the gas tuned down low enough that it will just barely cycle and lock the bolt back. If you get the belted case issue after that test, it's likely not port pressure at fault.
I think there are three main reasons for this. 1: is that the Lapua and Starline brass have thinner/less material at the head. Hornady cases are almost twice as thick and further up the case. 2: The dies have small bases and sharp edges exacerbating the problem. 3: It's a hot little cartridge and need to be careful with pressure spikes. The Mighty dies have a little larger diameter and a very nice radius at the base. I think that will help but not eliminate problems especially if loading hot rounds in Lapua and Starline brass.
I had that same problem with 308 Winchester in a National match Springfield M1A. Came to the conclusion that its in the brass. It only happened with one type of brass. Got rid of all the brass and back to the go to brass. Haven’t had a problem since.
Incipient case head separation? It’s the only thing I can imagine based on my experience, however, never case formed Grendel brass. I’m here to learn though! Thanks for the vid.! An observation: I’ve been watching your channel for years…… Your die pile is growing tremendously, like mine did in 1991! It’s as much fun as shooting. Those of you who don’t reload, this is one of the most fun you can have off the range! Good shooting to all my brothers and sisters!
I'll agree reloading is fun...the most fun? Eh, to each their own. ;) However I do blame JRB for getting me addicted to reloading! THANKS JOHNNY/SHANNON! My biggest problem now, besides components, my coworkers think I'm some sort of nut case. This is worse than my hot rod addiction.
I know you are trying not to overwork the brass, but you can definitely see the die is a significant distance from the shell holder when you are sizing. I think while forming, you should go all the way down until you get some cam over to get more of that case web sized, and then on subsequent sizings you could back the die off to make it fit your chamber better.
I had a similar problem on my 6.5 Creedmoor AR. When I changed from a carbine to rifle length barrel it got better. It appears that the bolt was unlocking before pressures were coming down sufficiently. I even ripped a few pieces of brass in half. My 22 Grendel has a rifle + 1 gas system and I don't have any problems. Maybe put an adjustable gas block on and shoot them with the gas off and see if you have the same problem
Just commented with some similar, but I definitely think this could just be overgassed. I was getting dented necks and sharp semi-circle rings on hornady factory ammo and getting the gas dialed in fixed things up for me.
I had a simular situation with 300blk reformed from 5.56 cases in an ar platform. Just like Johnny I miscalculated the charge weights and I was a grain to a grain and a half over charged.
I’ve got the same thing happening after 2nd firing is when I noticed it (possibly has happened with first firing of factory loaded ammo tho). Savage 110 switchback. 6 ARC bolt action rifle. The gun also punches primers often. Definitely more punched primers at the upper ends of powder charges but it also punches some in factory hornady 108 match ammo, which I assumed was loaded to lower pressures for AR-15. This is all hornady factory ammo brass and using hornady dies. The rifle shoots extremely well tho. Not sure why it’s punching primers. Haven’t measured firing pin yet. Federal 210M and cci large rifle primers as well as whatever hornady loads in their factory ammo are all showing this. Also getting tighter bolt closure on some reloaded rounds that have been full length sized.
Too much pressure in gas guns can do odd things...I'd be interested to see if the same thing happens in a bolt gun. As an aside, the 6mm ARC is limited to 52k PSI, mainly because the AR bolt is less than beefy when opened to the ARC/PPC bolt face size. I'd take a close look at the bolt lugs after any over-pressure loads, just to be on the safe side.
@@nathanbegovich6173 Aye, you can do the same with the .450 BM, it's restricted to 36k PSI for the AR platforms, but can be boosted significantly in a bolt gun.
Johnny, I know this doesn't pretain to this but I remember in a past video about trying to get a consistent crimp with your lee factory crimp die. I use feeler gauges in between the peddles raise the ram up and adjust it until I feel a bit of a drag.
I had the same problem with sizing .762x39 brass to grendel. After the first firing and resizing, they would no longer fit the chamber! Caint remember the brand of brass though! They also got that belted look to them as well. By caliper at the head were belted area was seen, was expanded to the point of no longer fitting the chamber!
I had a similar problem with some brass in my Mosin Nagant. Some cases wouldn't chamber. Too big at the base. With a standard size die the case couldn't be sized clear down to the rim. I found a Lyman shell sizer that full length sized clear to the rim. These shell sizers were used with a mallet or arbor press to push the case into the die. You then used a punch to remove the case. This fixed my problem. Perhaps sacrificing a full length size die by cutting it off just below the shoulder so you could size the case down to the base will help prevent this shoulder from forming.
I have been using SB dies for my Grendel and have not had any of these issues. It's not difficult to take the before and after measurements when sizing to see the effects. You should also check your fired brass to against the cartridge dimensions to make sure your chamber isn't oversized. if so, you will see it in the measurements and when you go to resize it back down (especially with a small base die) you can deform the brass. The shiny part at the bottom of the case is where it wasn't encased by the chamber... looking closely you can see the scratches from the chamber wall when expanded and extracted. If the HS is excessive you will also have issues
the exact same thing happened to me... I resized lapua 6.5 grendel brass down to 6 arc, loaded and fired them, went to resize for the next loading and had thick rings like that around the case head.
Great review. Might be the odin barrel. I'm on my 2nd barrel in 6.5cm from them and first barrel I was getting that same ring on realods and factory ammo. Odin took barrel back n sent me a new barrel. The new barrel is still doing it but not as bad. I'm where ur at I loaded some fl size n some with small base to see if that's causing the pressure problems. My ballistic advantage barrel does not have this problem. The odin barrel shoots great groups BTW. But I'm thinking I either have to download a lot or sell the barrel. It's frustrating wasting components lol. I think odin has some bad chambers or really tight chambers .
I've had my Grendel do that. It's firing slightly out of battery. It was the 120g Hornady ojive being jammed in the lands. Seat you bullets a couple thou deeper
I had exactly the same thing happen with Lapua brass in a 6.5 Grendel AR. I was trialling Leverevolution with 123gr SST. I should of stopped when I saw my loads approaching 2600fps out of a 16" barrel (Alexander Arms barrel and bolt). All of the silly fast loads fireformed into a belted magnum.
Spitballing here, similar to a Glock having an unsupported chamber maybe the combination of where the chamber ends and the spicy loads playing tricks with you. Another thought would be to possibly turn the gas off on your adjustable gas block...
Never seen 6 arc brass available ever since its been out! Signed up for so many alerts but as soon as I got an alert and went to the site the brass oss was sold out. Just ended up buying 500 rounds of 6mm arc and I reload them
Have been shooting a wildcat round (6 RAT) made from 6.5 Grendel by fire forming a 40* shoulder 0.800 forward. Nice accurate round that is easy to push 105 class bullets @ 2750 fps. Thought I'd try a 6 ARC just to have factory brass availability, well turns out ARC bass is like rocking horse poop. Have formed 6.5 Grendel Alexander Arms brass (think it is made by Lapua but could be wrong) into 6ARC with Hornaday dies and shot through Ballistic Advantage 22" barrel. Same result as Johnny but after 6 loads and only on the cases that were exploring the edge of the envelope. When confronted with early extraction issues I've employed the use of a weighted carrier to good results, think this will be my next move along with reasonable loads 1/2 to full grain under max.
Timing. If the bcg is going rearward super fast with too much gas it can cause the pull of the case out of the chamber before the pressure is totally out of the case. Its super hard on extractors, and because the case is partially removed from the chamber before the pressure is down it can case that portion of the case (bottom) to expand more than that portion still in the chamber.
Oddly, I recently read a forum thread from someone having the same "belt" issue. It doesn't seem like they came to many conclusions besides reduce the load. If you're curious find the thread '6mm ARC "sane" loads?' on the accurateshooter forum
I’m getting that belt on all my Hornady 6mm ARC brass reloads using the Hornady Custom FL sizing and seating dies. Reloaded brass 6 times and zero have broken on that spot so far.
The case should sit in the chamber all the way up to the extraction groove. The counter bore in your barrel might be too deep, leaving part of the case unsupported.
@@FullSendPrecision You are right though. Barrel smiths/rifle builders absolutely do need to know what the optimum depth and angle is for the cartridge they are chambering. We’ve seen this before though where higher charge weights with non-optimized gas systems kick out belted cases. Run that exact cartridge/load in another rifle with a correct port location/diameter and it ejects without any belt, looks almost-new.
What I found in my experience is that the reloading dies are chambered too short. I have 4 different brands of 6mm ARC FL dies and all of them will do this if I only bump the shoulder just enough. Most of them wont even touch the shell holder. If I make them cam over it bumps the shoulder way too much and over works the brass or causes gases to escape past the shoulder when I fire them. Best combination I found was L.E Wilson FL die and RCBS #32 shell holder. It still creates a small ring but not a belt. I have both a bolt action and an AR 6mm ARC and both of them are chambered on the longer side of SAAMI Specs which is the main issues with a lot of people because it's such a new cartridge. Most gun manufactures reamers are still on the longer side of SAAMI specs and hasn't needed to re-sharpened them (which in turn makes them a little shorter and make the chamber a little shorter).
Measure the case heads prior to forming, after forming and after firing. You said the primer pockets were smoked after 6 firings. I have a feeling that even though the 6 ARC has a 52K psi rating vs the 224 Valkyrie’s 55K the brass life of these small high performance cartridges is significantly lower than more traditional ones. Plus the charges your using are probably at or above max exacerbating the issue.
There are guys who have shot the head stamps out of Grendel brass with 20+ loads, namely Lapua brass. I’ve never lost a primer pocket in 6.5 Grendel with Lapua or Hornady brass in the past 13 years. I have lost primer pockets in older LRP PPU brass, as well as Federal brass. An interesting thing with Federal brass is that I will only get a few loads in the AR-15s with it using moderate charge weights well under 51,800psi, but when I loaded it in a Howa bolt gun, I was pushing way past that with stout loads under 129gr SST, primer pockets stayed perfectly tight. My preference is Lapua brass though. I think I still have all of my original Lapua brass when they were still sold in cardstock boxes, except for 1 piece I sectioned that was sized too much with Imperial Wax. Switched to Hornady One-Shot and haven’t looked back.
More power to those who reform brass. I have done that in the past but will not bother to ever do it again. Not that it doesn't work but if one wants there loads to be consistent the brass has to be consistent. I like to use the same head stamp. When you reform a lot of cartridges you need to neck turn and that brass if reformed will not be the same spec as the correct case with its appropriate headstamp. The only exception to reforming brass I might have is for 300 Black Out. But if you can find the brass it's still better to buy the correct brass and not reform brass. I have a lot of 30-06 cases I modified to 25-06 and 270 that I wish I hadn't. You can't change them back.
I thought I would make 6arc with 6ppc brass but same result the 6arc was smaller at the base above the extractor groove than the ppc brass by.003-.004 and sizing it in the hornady 6arc die left a nice little shallow belt.
It’s a headspace and timing issue. The bolt is unlocking prior to the projectile leaving the muzzle. I would switch to an adjustable gas block and tune out the system. High pressure rounds will expose any issues you may have. I test my rifles with slightly over pressure rounds to see if the system is tuned properly. This is a dwell time issue. Just take your time and tune the system to the load. If that doesn’t work then back down from the pressure curve.
I get similar results in my 30-06 Browning A-Bolt with factory ammo. If I just neck size or bump 0.001” - no problem. I think the chamber is large compared to factory brass.
Ran into belting problems with my 9mm. Rcbs die shaped perfect, but my Hornady custom belted bad. Found out the Hornady was shaping my case O.D .015" to .020" undersized. Crazy
This is a Starline brass issue, at least it was for me...I've had several batches of Starline 6.5 grendel brass that did this...they weren't quite as bad as yours but mine would swell in the same spot...I tried 3 different dies and I even bought a new barrel and it still did it...But I had no issues once I switched to Lapua and I even bought a 100 pieces of Hornady and had no issues with it, only the Starline...and I had 3 different lot numbers of the Starline and they all did it...
I had the same thing with starline only it was from the 120 eld not being seated deep enough and jammed in the lands letting the bolt close just enough to fire a bit out of battery. After seating deeper same charge was doing fine
This has been seen before. If you look at the hornady brass cut out it has more material build up in the corner where the wall and base meet. Supposedly this helps combat that issue.
@@MrBoostin18 this begs the question, "What is the chamber pressure?". I wonder if JRB could team up with Bolt Action Reloading and get a pressure number?
PLEASE READ!!!!! I’m in the process of forming 7.62 lapua to 6arc with Hornady dies. Ran through Grendel die first with expander removed, no problem. I annealed with induction annealed to ~750°f verified with Templar. Tried to run through 6arc die and belted one. Neck was fine so tried again and belted another. Check sammi drawings. 6arc and 6.5 Grendel have the same shoulder and base diameter with .441” at base. 7.62 is .002” wider at .443”. My Grendel die measured .440” at base while my arc die measured .4345. My lapua brass measured .442 after the Grendel die with a slight polish at base where is started to be sized, but the two belted pieces now measure .445 where the arc die belted, and mushroomed the base. I contacted Hornady about the die possibly being out of spec and their response was “ you are using our sizing die as if it is a forming die which it is not. If you choose to keep trying to run 7.62x39 you will need a forming die.” I’ve contacted them again with no response and ordered a die from mighty armory. I’d like to be in contact with you to raise awareness as this cartridge is becoming increasingly popular with little to no support. You can get the word out with high views in such short time.
The brass I've resized with the Mighty die measure .438 at the base. I think you should still keep you charges on the low side with Lapua brass if you want to get some life out of it. I'm using 28.2gr of Lever and think I could go to 28.7gr without a problem, but case life would be short.
I doubt it has much to do with pressure. I've had the same problem with European 6.72x39 formed to 6.5 Grendel. PPU and S&B formed a ridge that made the brass unusable in my Faxon barrel, I went to Winchester 7.62X39 brass it formed into usable 6.5 cases without a problem. After measuring the case heads the European stuff was to big by 3 to 4 thousands. I'm guessing now. USA specs on Grendel chambers are smaller than 7.62X39 chambers. No problem with Hornady brass, but I couldn't get small primers so I had to form 7.62X39.
This looks like there is unsupported case, such that when you over-pressured, some of the brass flowed outward where the case was unsupported near the extraction rim.
I have 2 different barrels and shot factory and resized 6 arc, 6.5 Grendel (Hornady and Starline) and 7.62 x 39 and have had belts on all of them, sometimes after 1 firing and I'm loading close to max but not over or real hot. Hornady and Lee dies. The unsupported area between the chamber and the bolt appears to cause just enough bulge then the dies seem to push it down instead of back in. I'm thinking of opening mine up to a 6 AR chamber, keep using the 6.5 Grendel and never look back. Excellent video, I have found very little info on this but didn't think it could be just me.
It undersized the base, you fired it hot, it reformed to the chamber. Its like fireforming. The unsupported part of the case will always sacrifice material. This is why the case head portion looks funky. I have seen it before. I have nothing but problems with PPU brass. It is undersized internally and loose primer pockets.
I am using the RCBS sb dies, and don't have that issue. But my barrel and bolt are matched, I have made 7.62x39 IMI brass into 6mm ARC and have not seen this in my gun yet.
I’ve got a question about the go no go primer pocket gauges you use. Can you take some measurements of the two and let us know what the sizes are of both sides of both gauges in thousands please and thank you.
Ive seen this is my 6.5 PRC . But I did not have small base dies. I think it was just old wor out brass at 1st untill it happened to a few twice fired Hornady brass.I know I was over MAX load.
I'm also having to resize 6.5 Grendel also because Hornady 6mm ARC has been unavailable for over a year. If Hornady stepped up and actually made enough 6mm ARC brass we wouldn't have this problem.
I was having the same problem with factory loads. I sent it back to Odin Works, they called me today and said it was a chamber issue and that they’re sending me a new barrel.
I’m having the same issue on my Grendel with Lapua brass. It’s over pressure. I run my Grendel hard and if I back off slightly it doesn’t do it anymore. I use Redding type S full length bushing dies.
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Belted cases are seen in 6.5 Grendel AR rifles with 22” or 24” barrels. Bolt is unlocking while chamber pressure is too high. It’s called dwell time. Some powders that work ok in a 20” or shorter barrel will not work in the longer barrel.
After seeing the inside of the cases, I'm less worried for you now. Thanks for taking the time to do that.
Late to this thread, but I just went through the same issue even when sizing Hornady cases from Hornady ammo. The issue seems to be the Hornady die is too aggressive a sizer. It is cut even closer to a small base die. My Hornady die is measuring .4350" at the die entry. I also have 6.5 Grendel and the die entry is .4380 to .4385". 6 ARC chambers are SAAMI spec if the .200" dimension is .4426" and a -.002" tolerance is allowed. My chamber is .441" at the .200" dimension (thus it is tighter than minimum), and the case heads start at .438" new and grow about .0005" each firing. The die sizes just below the .200 line and the die is hitting the thick part of the case web which has grown to .441". Therefore the die is trying to reduce the case head material by about .006", and that results in a belt as per the picture. Spring back will result in a case diameter above the belt of about .437". The only cure is to use a different makers die, or hone the Hornady die out to about .4385" . The Hornady is also oversizing the shoulder diameter from .431" down to .4255". Therefore the die will work for converting new 6.5 Grendel brass to 6 ARC, but will fail when sizing the fired brass after about 3 uses. Next step for me is to wait for my LE Wilson die to show up, and just use the Hornady die for converting new brass. I may chuck the die in a lathe and use a boring bar to cut .003 to .004" off the inside to match the LEE die a friend lent me.
Headspace!
Bolt face depth. 2 diff on the market for grendel bolts.
If you are using the .036 and need the .025 the brass is streching
This happened to me using a fast burn rate for bullet weight load. Case head was bulged a bit and plowed a belt around the bottom upon resizing. Did not see case head separation signs.
Have been watching your channel for some time now and I have to say that your videos are informative and entertaining. Have learned a ton from watching and have used the information garnered from watching the videos. Keep up the good work.
Well, Ive been re-forming 6.5 Grendel brass, and I ran into this issue. I believe it is from the full length resizing die pushing the brass into a pile at the bottom of the case.
I hadn't even fired the brass in my 6mm ARC rifle yet. One other thing to note, is that my ridges are considerably more narrow, and more towards the bottom of the case. Also, I did experience a little of this while resizing real 6mm ARC brass. These were reloads, but they were TAC and CFE223 powder, and not anywhere near max load, rather closer to minimum loads.
I just got another batch of once fired 6.5 Grendel brass (40 pieces) and I'm gonna be resizing it this evening. I'll figure out a way to post or send you pictures, if re-forming causes this anomaly.
Really appreciate and like these videos, as I am learning a lot more than the 40 years on my own.
Thanks Sean!
I just resized a 6.5 Grendel case and noticed a very slight belting line in the exact spot as in Johnny's video. Like you, I also came to the conclusion that it is a result of a slightly over pressured (expanded) case in the full length sizing die.
This is the exact same conclusion I’ve came to 6arc brass only through my 6arc. Thanks for cutting one in half and investigating the problem.
Soft case heads and too much pressure. (Bolt opening too early)
That band is from bolt head support. Its case head swell from. Again. Soft brass & or too
Much pressure!
I was reading my Gendel handbook an dont ya know this isue is know !! It is a result of the bolt opening too soon!
I am glad you did a video on the subject because I have a 6 ARC and I am useing 6.5 Grendel brass Star line for it
It has a odin works barrel
I get the same thing on my 6.5 Grendel some times. One issue might be powder burn rate and or over pressure. Glad you brought this issue up..
I reckon you achieved a huge amount !!!!!! And thanks for doing the investigation !!!!!
I'm with you as to it being a minimal danger episode .... Goes to show there's something new happening in the reloading experiences journey ..!!!!
I just received 1000 once fired 7.62 x39 brass and almost half had that little ring just above the head. I lost 10 out of 500 due to not lubed enough in the neck and shoulder area. I left the bullet expander in the die and it did help. Thank you for the post. 6 ARC brass seems to be impossible to find. I'm gonna size and send them from behind a wall.
First time I ever saw this was on a buddy’s 28” RLGS 6.5 Grendel over 10 years ago. Same load in a 20” RLGS Grendel did not exhibit this symptom. If you have a gas system driven with a higher charge weight, with too much plug dwell time, the bolt will unlock too early. He could actually load the 20” RLGS with higher charge weights and nothing, but the 28” RLGS would produce those “belted magnum” like symptoms.
Same issue, and was due to not lubing case enough when sizing, none occurred after firing. I took all the belted ones and filed off the belt, checking with a case gauge. Work fine now, and I learned to use enough lube!
I am once again petitioning for subsonic Grendel
That's amazing, they actually look exactly like factory belted cases.
If memory serves the brass hardness/strength should be in the ballpark of 200 +/- 10 on the Brinell scale. Check hardness to make sure the material has not been annealed.
The PPU ridge/ring is what I see on all European brass (PPU, BELOM, GFL, GECO, NORMA, etc.) that was formed from 7.62x39 and that's because their case head is bigger in diameter compare to American brass including PMC. I commented this on your forming video.
Agreed! Privi Patrisan loaded grendel ammo had a "bad batch" and recall years ago and were blowing brass and locking up guns. You're spot on in your assessment!
I was reading online and some sources say that true 7.62x39 is actually slightly tapered. If so that would explain the ring, especially when using a small base die. If you have some more unaltered 7.62x39 Lapua brass measure the width at the shoulder and then measure the width just above the webbing of the case and see if there are any differences.
On the stuff I read it seems like there was some gray area RE: 7.62x39 brass, sort of like the difference between .223 and 5.56. It is conceivable that Lapua has a slight taper (thus causing that ring) whereas other manufacturers don't do that.
7.62x39 is surely tapered. Its even visible. I have reformed 7.62x39 lapua to 6.5 grendel. But the cape capacity was WAY to small to be usefull, 5 grains of water less if i recall correcrly.
Thats 10% or even more difference! Makes it impossible to mix with other brass. Lapua and hornady grendel brass is basicly the same, 0.2 grains difference max.
My SPR clone used to do that randomly with once fired LC brass when I was chasing Mk 262 performance. It would do it at low pressure (FPS in the 2500 range), normal pressure, slightly high pressure (2700 tops). All powders, all primers, 2 different sizing dies, mostly 77gr SMKs and CCs. I thought maybe the brass was old machine gun stuff, just bad, so I used some of my own verified once fired stuff, same results. Had a smith take the gun apart and check everything, all in spec. Rainier barrel with a fail zero BCG. We never figured it out, so I just switched to Winchester brass and it never happened again, even with hotter loads. I'm absolutely no help.
For a second I thought you have created a new cartridge, 6.5 Grendel Short Magnum.
I just read about this in Glen Zediker’s book Handloading for Competition (p198 if you have it). He says if the gap between the bolt face and the rear of the chamber is too wide you can end up with this step forming and the rifle isn’t safe to shoot.
Others have said it could be over gassed and extracting too soon whilst pressure is too high, which sounds reasonable too. At 2:25 the case in the centre looks like it has a dent from the extractor, which might make sense if the extractor was yanking on the rim before the pressure has dropped.
Just my thoughts and I’m certainly not an expert!
nice video. thx for chasing this issue
I've only converted Star Line and Hornady brass the same way you did here with a standard sizing die then running an expanding mandrel through it to set neck tension and I've had the same results you did here except I don't anneal until after I fire form ... I honestly think using the SB sizing die is pushing brass into places it's not supposed to be and also agree your ejector grove looked squished on the brass you cross sectioned and that also tells me your brass is moving in ways it's not supposed to. It might have something to do with annealing the brass then using the SB sizing die to form it but it's definitely interesting. Great video as always keepem coming brother!!
Just completed my rifle and I read somewhere that Hornady may have some out of spec dies. I went with Lee dies and formed from 6.5 Grendel virgin brass. Fire formed a couple today and didn’t have the belted ring issue you’re having. I’ll gladly order some Lee dies and send them your way if you’re interested. I feel I owe it to you as much as I’ve learned from you! Thanks Shannon!!
@@jacobjohnson6766 did the die change solve the problem?
When I first saw this and I’m no expert. I instantly thought the shell was ejecting before pressure was released allowing the back to expand out. I originally was thinking it was a chambering flaw, but since it’s not every case that eliminated that idea.
You start winning with those. Everyone is going to want one.
Oddly timely.. I just had a similar event. I was shooting some factory ammo (108 match/105 black) on a new odinworks barrel. My first 10 rounds were on the gas setting that I dialed in on break-in day and I was getting bent necks and that ring. In my case, the ring appeared to be in a semicircle around half of the case. I spent a few rounds turning down the gas and the neck issue and rings went away after that.
My 6 ARC is at Odin works now getting looked at, I was having the same problem with factory rounds.
@@boone9875 that's not encouraging.. hopefully dialing the AGB was enough so that I don't see it again, but I'll definitely be keeping an eye on it.
I can tell you I have only had this happen with SPICY magnum loads.
My Arc brass was all Hornady grendel resized. None did that.
That's a classic case of way overpressure. I've had it happen when pushing max pressures on on wildcats with no load data.
This appears to be the classic symptoms of gas guns of either the dwell timing is too short before bolt starts unlocking from battery or the gas port pressure (not overall case pressure) is too high and unlocking the bolt too quickly after the correct dwell delay.
If it was a dwell time issue, that would likely happen on nearly all compatible bullet weights and powders that are safe full power loads.
If it is a port pressure issue, that would mainly be influenced by powder & bullet combo. An adjustable gas block would just add a variable to the mix.
Probably a good diagnostic step would be run the fastest compatible powder that is listed on published reloading data for a given bullet weight and get the gas tuned down low enough that it will just barely cycle and lock the bolt back.
If you get the belted case issue after that test, it's likely not port pressure at fault.
I think there are three main reasons for this. 1: is that the Lapua and Starline brass have thinner/less material at the head. Hornady cases are almost twice as thick and further up the case. 2: The dies have small bases and sharp edges exacerbating the problem. 3: It's a hot little cartridge and need to be careful with pressure spikes. The Mighty dies have a little larger diameter and a very nice radius at the base. I think that will help but not eliminate problems especially if loading hot rounds in Lapua and Starline brass.
I had that same problem with 308 Winchester in a National match Springfield M1A. Came to the conclusion that its in the brass. It only happened with one type of brass. Got rid of all the brass and back to the go to brass. Haven’t had a problem since.
Incipient case head separation? It’s the only thing I can imagine based on my experience, however, never case formed Grendel brass. I’m here to learn though!
Thanks for the vid.!
An observation: I’ve been watching your channel for years…… Your die pile is growing tremendously, like mine did in 1991!
It’s as much fun as shooting. Those of you who don’t reload, this is one of the most fun you can have off the range!
Good shooting to all my brothers and sisters!
I'll agree reloading is fun...the most fun? Eh, to each their own. ;) However I do blame JRB for getting me addicted to reloading! THANKS JOHNNY/SHANNON! My biggest problem now, besides components, my coworkers think I'm some sort of nut case.
This is worse than my hot rod addiction.
I know you are trying not to overwork the brass, but you can definitely see the die is a significant distance from the shell holder when you are sizing. I think while forming, you should go all the way down until you get some cam over to get more of that case web sized, and then on subsequent sizings you could back the die off to make it fit your chamber better.
I had a similar problem on my 6.5 Creedmoor AR. When I changed from a carbine to rifle length barrel it got better. It appears that the bolt was unlocking before pressures were coming down sufficiently. I even ripped a few pieces of brass in half. My 22 Grendel has a rifle + 1 gas system and I don't have any problems. Maybe put an adjustable gas block on and shoot them with the gas off and see if you have the same problem
Just commented with some similar, but I definitely think this could just be overgassed. I was getting dented necks and sharp semi-circle rings on hornady factory ammo and getting the gas dialed in fixed things up for me.
I had a simular situation with 300blk reformed from 5.56 cases in an ar platform. Just like Johnny I miscalculated the charge weights and I was a grain to a grain and a half over charged.
If that were the case a heavier spring may have remedied the problem. I'm assuming this is on a ar platform ofcourse.
@@mikebeddingfield2144 with both a adjustable gas block and a heavier buffer I fixed the problem
Any idea what kind of velocies you get from 22 grendal? Also does it feed reliably? Seems like the best ballistics you can get from an ar15
I’ve got the same thing happening after 2nd firing is when I noticed it (possibly has happened with first firing of factory loaded ammo tho). Savage 110 switchback. 6 ARC bolt action rifle. The gun also punches primers often. Definitely more punched primers at the upper ends of powder charges but it also punches some in factory hornady 108 match ammo, which I assumed was loaded to lower pressures for AR-15. This is all hornady factory ammo brass and using hornady dies. The rifle shoots extremely well tho. Not sure why it’s punching primers. Haven’t measured firing pin yet. Federal 210M and cci large rifle primers as well as whatever hornady loads in their factory ammo are all showing this. Also getting tighter bolt closure on some reloaded rounds that have been full length sized.
You guys crack me up with the brass forming. Just buy the correct brass.
You guys buying brass crack me up. Just buy loaded ammo.
Too much pressure in gas guns can do odd things...I'd be interested to see if the same thing happens in a bolt gun. As an aside, the 6mm ARC is limited to 52k PSI, mainly because the AR bolt is less than beefy when opened to the ARC/PPC bolt face size. I'd take a close look at the bolt lugs after any over-pressure loads, just to be on the safe side.
I believe it also goes up to 62kpsi in bolt guns
@@nathanbegovich6173 Aye, you can do the same with the .450 BM, it's restricted to 36k PSI for the AR platforms, but can be boosted significantly in a bolt gun.
I had it happen with some 10mm pistol brass and some 6.5 PRC.The 6.5 had been over pressure.The 10mm was range brass I picked up
6arc is looking pretty cool. After watching your video I was thinking you were creating some kind of belted minimag.
Johnny, I know this doesn't pretain to this but I remember in a past video about trying to get a consistent crimp with your lee factory crimp die. I use feeler gauges in between the peddles raise the ram up and adjust it until I feel a bit of a drag.
I see this on some of my 6ARC brass when the loads get extra spicy. Hornady 6ARC brass, hornady dies, faxon barrel and bolt.
I had the same problem with sizing .762x39 brass to grendel. After the first firing and resizing, they would no longer fit the chamber! Caint remember the brand of brass though! They also got that belted look to them as well.
By caliper at the head were belted area was seen, was expanded to the point of no longer fitting the chamber!
I had a similar problem with some brass in my Mosin Nagant. Some cases wouldn't chamber. Too big at the base. With a standard size die the case couldn't be sized clear down to the rim. I found a Lyman shell sizer that full length sized clear to the rim. These shell sizers were used with a mallet or arbor press to push the case into the die. You then used a punch to remove the case.
This fixed my problem. Perhaps sacrificing a full length size die by cutting it off just below the shoulder so you could size the case down to the base will help prevent this shoulder from forming.
I have been using SB dies for my Grendel and have not had any of these issues. It's not difficult to take the before and after measurements when sizing to see the effects. You should also check your fired brass to against the cartridge dimensions to make sure your chamber isn't oversized. if so, you will see it in the measurements and when you go to resize it back down (especially with a small base die) you can deform the brass. The shiny part at the bottom of the case is where it wasn't encased by the chamber... looking closely you can see the scratches from the chamber wall when expanded and extracted. If the HS is excessive you will also have issues
the exact same thing happened to me... I resized lapua 6.5 grendel brass down to 6 arc, loaded and fired them, went to resize for the next loading and had thick rings like that around the case head.
I noticed the markings on my 6 arc once fired brass. After resizing and loading they didnt want to chamber. I had a heck of a time getting them out.
Great review. Might be the odin barrel. I'm on my 2nd barrel in 6.5cm from them and first barrel I was getting that same ring on realods and factory ammo. Odin took barrel back n sent me a new barrel. The new barrel is still doing it but not as bad. I'm where ur at I loaded some fl size n some with small base to see if that's causing the pressure problems. My ballistic advantage barrel does not have this problem. The odin barrel shoots great groups BTW. But I'm thinking I either have to download a lot or sell the barrel. It's frustrating wasting components lol. I think odin has some bad chambers or really tight chambers .
I've had my Grendel do that. It's firing slightly out of battery. It was the 120g Hornady ojive being jammed in the lands. Seat you bullets a couple thou deeper
You can put brass in lathe or drill press and file down ring to fit in gun.
I had exactly the same thing happen with Lapua brass in a 6.5 Grendel AR. I was trialling Leverevolution with 123gr SST. I should of stopped when I saw my loads approaching 2600fps out of a 16" barrel (Alexander Arms barrel and bolt). All of the silly fast loads fireformed into a belted magnum.
Spitballing here, similar to a Glock having an unsupported chamber maybe the combination of where the chamber ends and the spicy loads playing tricks with you. Another thought would be to possibly turn the gas off on your adjustable gas block...
Magnums- they look so cool
Never seen 6 arc brass available ever since its been out! Signed up for so many alerts but as soon as I got an alert and went to the site the brass oss was sold out. Just ended up buying 500 rounds of 6mm arc and I reload them
I left a comment about this and starling one one of your videos 2 or 3 months ago.
Have been shooting a wildcat round (6 RAT) made from 6.5 Grendel by fire forming a 40* shoulder 0.800 forward. Nice accurate round that is easy to push 105 class bullets @ 2750 fps. Thought I'd try a 6 ARC just to have factory brass availability, well turns out ARC bass is like rocking horse poop. Have formed 6.5 Grendel Alexander Arms brass (think it is made by Lapua but could be wrong) into 6ARC with Hornaday dies and shot through Ballistic Advantage 22" barrel. Same result as Johnny but after 6 loads and only on the cases that were exploring the edge of the envelope.
When confronted with early extraction issues I've employed the use of a weighted carrier to good results, think this will be my next move along with reasonable loads 1/2 to full grain under max.
Timing. If the bcg is going rearward super fast with too much gas it can cause the pull of the case out of the chamber before the pressure is totally out of the case. Its super hard on extractors, and because the case is partially removed from the chamber before the pressure is down it can case that portion of the case (bottom) to expand more than that portion still in the chamber.
Oddly, I recently read a forum thread from someone having the same "belt" issue. It doesn't seem like they came to many conclusions besides reduce the load. If you're curious find the thread '6mm ARC "sane" loads?' on the accurateshooter forum
I’m getting that belt on all my Hornady 6mm ARC brass reloads using the Hornady Custom FL sizing and seating dies. Reloaded brass 6 times and zero have broken on that spot so far.
That happened to me using lee dies and rcbs till I took out the decap rod out and lubed the hell outta the case. No more belt
Correction I use lee and rcbs dies that cause the belt till u bought hornady full size die and removed decap and that got rid of the belt
Have had the same thing when overpressure with starline 6.5 grenxel and hornady 6 arc brass. Also I use the SB die
It looks like the classic overpressure line to me . With the primer pockets loose at only 6 firings , that would suggest the same thing .
The case should sit in the chamber all the way up to the extraction groove. The counter bore in your barrel might be too deep, leaving part of the case unsupported.
It does look like high pressure signs w/ unsupported brass in a pistol .
It’s early unlocking due to too much plug dwell with higher charge weight.
@@LRRPFco52 makes perfect sense.
@@FullSendPrecision You are right though. Barrel smiths/rifle builders absolutely do need to know what the optimum depth and angle is for the cartridge they are chambering. We’ve seen this before though where higher charge weights with non-optimized gas systems kick out belted cases. Run that exact cartridge/load in another rifle with a correct port location/diameter and it ejects without any belt, looks almost-new.
At high pressures you start to see brass flow like a liquid. It flowed to the point it could best 'pool' considering the pressure at the time.
What I found in my experience is that the reloading dies are chambered too short. I have 4 different brands of 6mm ARC FL dies and all of them will do this if I only bump the shoulder just enough. Most of them wont even touch the shell holder. If I make them cam over it bumps the shoulder way too much and over works the brass or causes gases to escape past the shoulder when I fire them. Best combination I found was L.E Wilson FL die and RCBS #32 shell holder. It still creates a small ring but not a belt. I have both a bolt action and an AR 6mm ARC and both of them are chambered on the longer side of SAAMI Specs which is the main issues with a lot of people because it's such a new cartridge. Most gun manufactures reamers are still on the longer side of SAAMI specs and hasn't needed to re-sharpened them (which in turn makes them a little shorter and make the chamber a little shorter).
I have definitely had this when forming from .243Win to 6.5x50Arisaka
Good video
Measure the case heads prior to forming, after forming and after firing. You said the primer pockets were smoked after 6 firings. I have a feeling that even though the 6 ARC has a 52K psi rating vs the 224 Valkyrie’s 55K the brass life of these small high performance cartridges is significantly lower than more traditional ones. Plus the charges your using are probably at or above max exacerbating the issue.
There are guys who have shot the head stamps out of Grendel brass with 20+ loads, namely Lapua brass. I’ve never lost a primer pocket in 6.5 Grendel with Lapua or Hornady brass in the past 13 years. I have lost primer pockets in older LRP PPU brass, as well as Federal brass. An interesting thing with Federal brass is that I will only get a few loads in the AR-15s with it using moderate charge weights well under 51,800psi, but when I loaded it in a Howa bolt gun, I was pushing way past that with stout loads under 129gr SST, primer pockets stayed perfectly tight. My preference is Lapua brass though. I think I still have all of my original Lapua brass when they were still sold in cardstock boxes, except for 1 piece I sectioned that was sized too much with Imperial Wax. Switched to Hornady One-Shot and haven’t looked back.
More power to those who reform brass. I have done that in the past but will not bother to ever do it again. Not that it doesn't work but if one wants there loads to be consistent the brass has to be consistent. I like to use the same head stamp. When you reform a lot of cartridges you need to neck turn and that brass if reformed will not be the same spec as the correct case with its appropriate headstamp. The only exception to reforming brass I might have is for 300 Black Out. But if you can find the brass it's still better to buy the correct brass and not reform brass. I have a lot of 30-06 cases I modified to 25-06 and 270 that I wish I hadn't. You can't change them back.
Probably the start of case head separation. Just cause the thickness is ok doesn’t mean the integrity of the brass is ok.
I thought I would make 6arc with 6ppc brass but same result the 6arc was smaller at the base above the extractor groove than the ppc brass by.003-.004 and sizing it in the hornady 6arc die left a nice little shallow belt.
This happens in 350 Legend when I'm way high in pressure. It won't size down enough to pass the case gauge, even with a small base die.
It’s a headspace and timing issue. The bolt is unlocking prior to the projectile leaving the muzzle. I would switch to an adjustable gas block and tune out the system. High pressure rounds will expose any issues you may have. I test my rifles with slightly over pressure rounds to see if the system is tuned properly. This is a dwell time issue. Just take your time and tune the system to the load. If that doesn’t work then back down from the pressure curve.
I got the same thing, used starline and lapua. I got a proof research barrel
JRB is the Elmer Keith of our generation. Wildcat to don't blow your face off!
I get similar results in my 30-06 Browning A-Bolt with factory ammo. If I just neck size or bump 0.001” - no problem. I think the chamber is large compared to factory brass.
Ran into belting problems with my 9mm. Rcbs die shaped perfect, but my Hornady custom belted bad. Found out the Hornady was shaping my case O.D .015" to .020" undersized. Crazy
This is a Starline brass issue, at least it was for me...I've had several batches of Starline 6.5 grendel brass that did this...they weren't quite as bad as yours but mine would swell in the same spot...I tried 3 different dies and I even bought a new barrel and it still did it...But I had no issues once I switched to Lapua and I even bought a 100 pieces of Hornady and had no issues with it, only the Starline...and I had 3 different lot numbers of the Starline and they all did it...
I had the same thing with starline only it was from the 120 eld not being seated deep enough and jammed in the lands letting the bolt close just enough to fire a bit out of battery. After seating deeper same charge was doing fine
This has been seen before. If you look at the hornady brass cut out it has more material build up in the corner where the wall and base meet. Supposedly this helps combat that issue.
But their primer pockets get loose as all get out after 4-5 firings
@@MrBoostin18 this begs the question, "What is the chamber pressure?". I wonder if JRB could team up with Bolt Action Reloading and get a pressure number?
PLEASE READ!!!!! I’m in the process of forming 7.62 lapua to 6arc with Hornady dies. Ran through Grendel die first with expander removed, no problem. I annealed with induction annealed to ~750°f verified with Templar. Tried to run through 6arc die and belted one. Neck was fine so tried again and belted another.
Check sammi drawings. 6arc and 6.5 Grendel have the same shoulder and base diameter with .441” at base. 7.62 is .002” wider at .443”. My Grendel die measured .440” at base while my arc die measured .4345. My lapua brass measured .442 after the Grendel die with a slight polish at base where is started to be sized, but the two belted pieces now measure .445 where the arc die belted, and mushroomed the base.
I contacted Hornady about the die possibly being out of spec and their response was “ you are using our sizing die as if it is a forming die which it is not. If you choose to keep trying to run 7.62x39 you will need a forming die.”
I’ve contacted them again with no response and ordered a die from mighty armory. I’d like to be in contact with you to raise awareness as this cartridge is becoming increasingly popular with little to no support. You can get the word out with high views in such short time.
The brass I've resized with the Mighty die measure .438 at the base. I think you should still keep you charges on the low side with Lapua brass if you want to get some life out of it. I'm using 28.2gr of Lever and think I could go to 28.7gr without a problem, but case life would be short.
Unsupported case with hot loads.
Check headspace and make sure you're bumping the shoulder back enough.
I doubt it has much to do with pressure. I've had the same problem with European 6.72x39 formed to 6.5 Grendel. PPU and S&B formed a ridge that made the brass unusable in my Faxon barrel, I went to Winchester 7.62X39 brass it formed into usable 6.5 cases without a problem. After measuring the case heads the European stuff was to big by 3 to 4 thousands. I'm guessing now. USA specs on Grendel chambers are smaller than 7.62X39 chambers. No problem with Hornady brass, but I couldn't get small primers so I had to form 7.62X39.
I have a 24” barrel and plus 2 gas tube, still does it. Factory Hornady 108 grain ELDM are in the lands
This looks like there is unsupported case, such that when you over-pressured, some of the brass flowed outward where the case was unsupported near the extraction rim.
I have 2 different barrels and shot factory and resized 6 arc, 6.5 Grendel (Hornady and Starline) and 7.62 x 39 and have had belts on all of them, sometimes after 1 firing and I'm loading close to max but not over or real hot. Hornady and Lee dies. The unsupported area between the chamber and the bolt appears to cause just enough bulge then the dies seem to push it down instead of back in. I'm thinking of opening mine up to a 6 AR chamber, keep using the 6.5 Grendel and never look back. Excellent video, I have found very little info on this but didn't think it could be just me.
It undersized the base, you fired it hot, it reformed to the chamber. Its like fireforming. The unsupported part of the case will always sacrifice material. This is why the case head portion looks funky. I have seen it before.
I have nothing but problems with PPU brass. It is undersized internally and loose primer pockets.
I am using the RCBS sb dies, and don't have that issue. But my barrel and bolt are matched, I have made 7.62x39 IMI brass into 6mm ARC and have not seen this in my gun yet.
I’ve got a question about the go no go primer pocket gauges you use. Can you take some measurements of the two and let us know what the sizes are of both sides of both gauges in thousands please and thank you.
Ive seen this is my 6.5 PRC . But I did not have small base dies. I think it was just old wor out brass at 1st untill it happened to a few twice fired Hornady brass.I know I was over MAX load.
I'm also having to resize 6.5 Grendel also because Hornady 6mm ARC has been unavailable for over a year. If Hornady stepped up and actually made enough 6mm ARC brass we wouldn't have this problem.
I had the exact same issues with starline Grendel brass. I got so fed up that I ended up scrapping the whole batch.
I had the same problem with Hornady dies ended up using Lee dies and had no more crushed necks.
Have you thought yet of trying a 224 Grendel build and loads yet? Thanks for all the great content!
I was having the same problem with factory loads. I sent it back to Odin Works, they called me today and said it was a chamber issue and that they’re sending me a new barrel.
Belted 6arc brass looks kinda cool
My 6.5 Grendel broke apart at the rings. Reloaded too many times. Yes , case head separation.
I’m having the same issue on my Grendel with Lapua brass. It’s over pressure. I run my Grendel hard and if I back off slightly it doesn’t do it anymore.
I use Redding type S full length bushing dies.