Does seating depth matter for load development?
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- เผยแพร่เมื่อ 28 ก.ย. 2024
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Nice test John, I will also note that the speed stat from the SM is all of 11 SD. Knowing that the speed was slowing with the seating depth, the fact that the SD is still only 11 shows a very forgiving recipe all in all.
Interesting test John, I have a problem comparing seating depth performance (accuracy) with only one round per depth. I think a minimum of 3 shots each depth so that one can see the potential precision of each group between the seating depths. Just me, and I know there are many ways to do comparisons. Thanks for sharing.
patience and hard wor surely rewards people...
Yes, I agree and do the same, a 3 shot group could reveal the most precise load yet shoot 1 inch right of POA.
Adjust scope in that case, not the ammo.
Plot the elevation vs seating depth in Excel, it there is a trend, it will show up there. Staring too long at a cluttered target will make you imagine things that are not there. I did a very similar test, but only looked at velocity. There was a very strong linear trend to slow down as the jump increases. At long range, this velocity difference is enough to account for an elevation trend on the target.
if this trend follows more than 1 shot, id be interested. definitely hope you continue to do this testing.
meaning take the best node, and the worst node, and regroup them at the same range and see if it stays true.
it matters for both head space AND powder compression (or even just powder free space within the cartridge)
Was hoping you’d circle back on this. Great recap!
Thank you
Interesting.
Enjoy the content! I am looking at building an f-class rig and doing my own improved cartridge. Just for fun and enjoy learning how to shoot better!
I’ve found that the widest node to be .050-.080 from jam in multiple guns and calibers
i agree with that
What's crazy is that 1 and 20 are an inch apart! What the heck...
My biggest problem is finding a barrel for an ar that is accurate. Always seem to find at least.07 jump. Tried multiple powders multiple projectiles can never get under 1.15 group
I can't afford a 2k barrel that will be sub moa with everything, so doing a proper seating depth group helps tremendously. I don't get what your test shows or doesn't show other than you got a badass rifle/powder/tip combo to make that little of a difference
What size target do you use for practice at 1000 yards
Where did you get the ammo case?
Those are called ClamTainers
Awesome test John! Thanks again. I see the annular ring on the bullets, did it help?
Still doing a lot of testing on the Nose Ring. More videos on that come. But so far, I've been getting good results.
I was so worried as I have a Panda 284 with a barrel having .5 inch freebore. Did some testing at 5.840 CBTO and am shooting half MoA consistently at 800 meters.
I dunno ar 3 hundreds of lands will changing seating depth make it any better.
Would be interesting to do the exact same test again but shooting them out of order.
Morning John. Love this test. I have 2 questions if you dont mind me asking. You mentioned your donuts have been pushed out? How does that process work? 2ndly, what target cam system are you using?
The donuts are pushed out when you run and expander mandrel or gage pin down through the necks. As for the target system, it's the Shotmarker.com system.
If seating depth doesn't matter for small groups in F-Class terms what does?
Seating depth is obvious, but what I want to know is how the new PRC designs with their much longer throats or leads affect accuracy compared to the old 7mm rem mag for example. Since the bearing surface of the bullet is much more exposed on the PRC and can be supported by the throat, does this lend itself to greater accuracy and alignment of the bullet with the bore? On the 7mm rem mag, almost no part of the bearing surface of the bullet is sticking out of the case on the 162 grain eldx for example. Its almost all ogive sticking out. As the bullet contacts the lands, does the PRC have better support on the back of the bullet therefore better alignment? Or does is it the case that is actually supporting the back of the bullet on the 7 mag, therefore adequate alignment? High BC bullets (and higher twist rates) seem to have much lower mechanical accuracy (short range) than the bullets with shorter ogives and a longer bearing surface and less nose cantilevered out into the barrel which must remain perfectly centered or your accuracy is screwed.
I'm shooting a 7 Rem Mag, with moly'd Berger 180 VLD's seated 3.430" long, at about 5 thou off the lands. There's plenty of bearing surface diameter out there with those long pills.
Currently looking at the Nosler RDF 180's and the Sierra 183's to see if there's any similarity in accuracy, but they have long tips and slightly shorter bearing surfaces. ( Looking at other "seeds" in case my supply of Bergers dries-up, or becomes ridiculously overpriced.)
28" Lilja 9-twist, H-1000, @ ~ 3000 fps.
Hmm...
thats one hell of a gunsmith, whats your free-bore
Yeah he’s good. My freebore is .220
On very high end rifle like the one used in this test, I guess seating depth may not be as relevant like on a factory rifle.
In benchrest competitions we test the seating depth. Very high quality barrels and actions (kelbly, bat...). Tuning your loads (with powder charge, seating depth, tuners) is related to your barrel harmonics. If you can't tune your loads or get inconsistent point of impact, then your barrel harmonics are inconsistent (big problem if you're looking for a accuracy)
That's 600m right? Show me a group all like number 1😂😂😂😂
Donut?
I totally disagree with your rather incomplete and narrow focused tests. Do 3 shot groups with VLD, ELD, RDF or whatever low drag bullets you desire and go up to a .160" jump, then reassess the findings.
As always thanks for such wonderful content. Question though, with all the discussion I've been hearing lately about all the things that don't matter for load development, it's becoming more and more difficult to say with any conviction what a solid development and reloading process should look like. What have you found in your experience matters?
Hi John! From my recent loads I found that with lower pressures and less speed, example: I dropped my speed down 340fps running less powder and now my 140gr nosler does not care where I seat it. Long as -3000 from jam and to short as 180k from jam. It just wants to group. So I am with you on this test. Also fun fact, my ES went down to 2fps from 16fps. 2510fps av 140gr nosler RDF 6.5mmCM using s365 Solchem Powder
Funny you bring this up. I shoot PRS gas gun division using 6 ARC. 6 ARC is a great cartridge BUT is extremely tricky to load for using temp stable extruded powders. (Very easy to over pressure if trying to get higher velocity) I've found that it really likes slower velocities. That's where it groups the best. I did a ladder test with VV N550 and hornady 105gr bthp's. The thought was I'll get more velocity out of a lower charge. Turns out the velocity was way slower than I would have liked BUT the grouping throughout the test was very good. (.690" For a factory gas gun that's very acceptable) I honestly didn't know what to make of it as it wasn't what I expected.
@@oif3vetk9 that’s good to hear. I didn’t do it on purpose until I checked the speed after the fact. My normal loads were 2950fps but very sensitive to seating depth. At 2700 it’s ok but bigger groups and slightly wider nodes than 2950. At 2510, it really doesn’t matter. I hunt mostly and I don’t shoot further than 300m, so I prefer the accuracy over speed, confidence in my store bought 783 is out of this world. Sub1/4 Moa at 100y. Love it. Would be cool if a channel could test this for us.
Great video, can you please tell me where you got the clear plastic storage boxes that your ammunition is in, thanks in advance.
Very nice. Just wondering which process comes first, finding the right load or seating depth? How do you know when to start playing with seating depth, as in how do you settle on a load?
I think it's hard to make a great barrel shoot bad, especially with good bullets that it likes. Awesome demonstration!
I really enjoy all of your videos. I just wanted to say I think most of us are watching these on a smart TV with no option to comment. We can "like + Subscribe" but thats it. TH-cam should realize this in their algorithm
Thank you and that's an interesting thing that I didn't realize. Either way I appreciate the support and all I can ask is keep liking the videos!!
17,18,19,20 - thanks for the good video!!
Glad you liked it.
I'd love to see a ladder test, three or five shots per load, done twice (ie repeated with the same load configuration). I think you'd be surprised the degree to which the shooter influences the test.
I strap mine into a lead sled. Minimal human error.
Seating depth is the second most important measurement in Benchrest i wonder why it doesnt matter in F-Class?
How do you think it affects pressure with that much of a change in depth
cool test john, I would also think the bullets ogive has a lot to do with the seating sensitivity. Some bullets i’ve fired went from 1 MOA to .25 MOA in 0.090 difference.
Now this is pretty awesome to see, I’ve done extensive testing on seating depth with different manufacturers projectiles and some have wide nodes and some well have stupidly narrow nodes so this could be the case, but you know what it shows a huge picture that at least the powder node you are using for the given projectile is working extremely well which finding is half the battle.
I commend you on sharing this John love your channel and what you do with it and congrats on the last day at SWN too massive achievement considering any battles but what you did was commendable 👍🏻
Thank you for the kind words and I'm glad these videos help.
Like and comment. Glad youtube suggested this.
Thank you
This make so much sense. Thank you.
No statistical significance in such a test. Either the design of projectile likes jump, or it doesn’t. If tens to hundreds of thousands of dollars are on the line and you believe that finding an optimal seating depth makes enough difference, go for it. Otherwise, shoot 10 rounds with some jump and ten without and find what worked best, then settle on a nice COAL that works.
Seating depth is important for those of us "hunters" who have to shoot at magazine length, maximum :) I usually start there and then fine tune, going in, in .005" increments... seems to me that different bullets are more or less forgiving to depth, verses rifle/ load/ powder, but I'd love to see you do a similar test!
I ran some ladder tests for my .284W and 6ARC, both on AR platforms. After some unusual circumstances forcing me to test very deep seating depths, I found my best nodes way down-on both. Not the best groups, but the widest nodes and damn close.
So you're seating deep on both of those cartridges?
Also where can i learn more about that .284W?
@@nativewarrior5052 My .284Win AR had a really deep throat (the reamer was cut for very long bullets) but I'm restricted by the AR-10 (.308 short action R700) magazine length. The wiki will give a ton more detail but the .284 win was developed as a semi auto to fit in that action length. It was ahead of it's time and really doesn't stand out without longer bullets though. If I had to do the build over again I'd have done it on a platform designed for long action, like the ARs that run .30-06. It's a sweet rifle but it's a project rifle that I'm still dialing in and debugging. Unless you are into strange cartridges and buggy guns I would recommend the 7mm-08. It's not quite as good but it's a solid cartridge.
Anyway, I'm back at like 120 thou in the .284 and 40-60 depending for the ARC. That was due to some feeding and reliability issues with the early guns and an Anderson upper not having feed ramps. Once I ground those in it fixed a lot of that.
@@userJohnSmith ok, im familiar with the 284 Winchester and the 284 AI version as well. Its the 7mm version of 30-06 and 270. Personally i have a bolt action 270 and would love a AR platform 270 which is made by one company that also does 30-06 chambered versions. I didnt realize it was the same type of large frame AR. For some reason i thought it was like 6.8SPC but 284 and fit in a AR-15 frame like 6 ARC does.
@@nativewarrior5052 Nope, had to do an AR-10. But it shoots lights out, when I'm not fighting with magazines or gas settings.
Guess I'm "cheating" with 6 ARC. I use a EC barrel tuner/brake. With the AR platform with a free floated barrel I guess I don't see the need (Kind of, stay with me on this) to play with seating depth. I load at factory depth, ladder test, find my node and let the tuner do the rest. Is it optimal? Probably not but it does save components. Now, with my M1A I did do seating depth. I got it down to a consistent .825" at 100 yds. The 6 ARC is about the same, some days a touch better but not much. Working on a new load of 109 berger hybrid/VV N540. Once I find the tuner setting it likes then I'm going to play with seating depth just for the fun of it. Like I said, haven't tried it with ARC yet. Using extruded powders/heavy bullets the velocity is down (Just above 2600 fps) but my SD has averaged in the 5 fps range. (10 shot strings, berger 105 hybrids/VV N150. We'll see how it does with the 109's and N540)
I think it would be interesting if you repeated this experiement to help prove whether any trends you might see are real or just luck of the draw.
Shot 9, 10, and 11 have similar vertical dispersion as you noted, but shots 7, 8, and 12 (immediately before and after this potential node) are in the opposite corner as shot 9. With only 20 thousandths difference in seating depth between 8 and 12 that would be quite the narrow node if it actually existed.
I'd be very surprised if the same test shot a second time (same charges and seating depth) gave the same potential nodes, because these results appear far more random than anything else. A couple small clusters that could be perceived as potential nodes is something that you'd see in a random dataset anyways, and if it's not a repeatable result then there's not much point in following those small random clusters.
Bryan litz says .015” off and beyond makes little to no difference with hybrids.
Oh my… you have yourself a very stable load there!
It took that seat depth variance, ate it for lunch, and spat out a fine group regardless of what you believe about the significance of seat depth.
If I were you I would be plum pleased with this result.
A 20rd group is not insignificant.
Interesting. I believe it comes more from the cartridge. I have no scientific proof but after years of testing I've noticed that on some cartridge vs others : .308win, 6NBR, 6PPC are sooo easy to tune and more important to keep the load in tune.
What does it do to the Chamber Pressures? The deeper Bullet must of raised the pressures! Chamber Pressures is the Critical concern here!
I question tangent bullets but definitely secant bullets
just my opinion
Thanks as always John, Set some of my 6.5 C's at 30 off the lands, and got great results, sub.250 but many one wholes, what's funny is Hornady's 6.5 C's ELD-X are 65 off and shoot .50 groups, really surprised at how good boxed ammo shoots now days. Am reloading the same seeds, but with H 4350
Glad you enjoyed the video.
Inconclusive 😂😂😂
you mentioned donuts being pushed out. What is your method to accomplish this
where do you buy those plastic round holders??
Thank you, this is very interesting. Do you ever seat into the lands? I have a theory that neck tension variations might make less of a difference when bullets are pushed into the lands (not enough to "jam" in Cortina-speak but enough that the force needed to start the bullet moving is signifcantly affected by engraving forces).
Unfortunately I don't have the equipment to test this properly, so it's just a pie in-the-skie theory but would appreciate tour thoughts?
I've tested in the lands and it can shoot good there but the problem comes when you have to pull a round in a match. There's always a chance you'll pull a bullet if it's too far stuck in the lands. Not a chance I want to take.
@@FClassJohn thanks for the reply. I am currently seating my bullets 0.5mm (20 thou) away from the point where they jam. I have chambered and extracted about 30 rounds without measurably changing seating depth (although that was all with a clean bore).
Any idea if your es/SD changed and how much?
At target my SD was 11.2 across all 20.
Well no, yes it matters😂😂😂
I think that custom rifles have wider nodes than factory rifles. Do you remember John if this is true when you were shooting the ruger ?
Donuts?
What I notice from the pattern is at first the shots were going int a straight line as you decreased the depth, then it got very erratic towards the end and the shots were more random.
Whats that software you used to draw the final chart with?
That’s just the shot marker software from the targeting system
If seating depth realy works... why can your shoot a awesome group one day but won't repeat the next... and be out by quite a bit
Simpliy because something has changed and you didn't notice :
- Because you believe that you didn't change anything to your reloading process, but in reality you did (neck tension...)
- Because external conditions changed (temperature, humidity, wind)
- Because you changed the way you hold your gun
Keeping a load in tune isn't easy...
I was an anti AR 308 shooter until I met the crew of CMMG in a Lake Ozark Bar. I agreed to try one in 2009. well I bought a complete Lower for $249.00 and commenced to building lowers, I am taking it to the range tomorrow to test some handloads. I still don't need another but if I did it would be a Cmmg.
I was working on a 243 AI shooting 70 gr Dierras with WIN 760. I tried various loads in increments of .03 of a grain. It was almost there but wouldn't quite repeat groupings. Almost gave up and decided to seat the bullets .002 deeper. The reloading gods were with me. Instant magic.
1 shot is spare to conclude much, typically would like to see 3 same depth to gauge any kind of consistency with barrel cooling between each set of 3. Would take longer but may show more reaI information the more shots with same depth is better for evaluating. Everyone has to draw their own size sample group that they are comfortable with. If 1 is yours, my hat is off to you. Thanks for sharing 👍.
John nice test! What I have found just like others mentioned below, is if we are mag feeding obviously we have to stay within the mag well length and try different ones inside that measurement. What I have found in when speaking with my gunsmith that chamgers or reams my barrel. I may not be saying it correctly because I don't know how reaming a barrel is done. But he tells me about a parallel throat or freebore before the lands Vs what you may find in a factory non custom barrel that is a funnel shape before the lands. So I have found in a factory style barrel the closer you are to jam or at jam the accuracy improves over further back. But with my custom barrels with the Parallel chamber I seat 100-200 from jam and have excellent results. And this of course is using the same bullet, powder and powder capacity. Something to also mention is loading the case and seating the bullet where you have a higher case powder capacity like a lightly compress load, not crushing powder and seating the bullet in further. I have found single digit SD and less dramatic ES from this method. But if you seat the bullet futher out closer to jam. I would start seeing an increase in the ES and SD. Just my 2 cents.
What an eye opener! Thank you for posting, John! - Alex
I've actually tested this method with my previous load development and will confirm with behalf of John that this does work. This was also before I watched John's video on it and just thought "what a coincidence". Mind you, I did this without a chronograph and developed a load within 30 rounds that shot a 0.71 MOA at 220 yards. This was not for benchrest or F-Class shooting, only hunting purposes. I tested the load 2 weeks later to confirm and it ahot right on the money.
I enjoy your videos, this one, not so much. 😊
1 powder charge
2 primers type
3 primer seating
4 Brass trim
..Fire forming, Annealing
Etc. etc. etc. etc. so on and so on.
You do all of these thing as best you can. “That’s good enough. Skip the seat depth test” ???
You can say it doesn’t make a lot of difference in your rifle, but not every rifle will react the same. It could be a significant factor just like all the other steps that were taken. Just not as significant in your rifle.
If a person goes through a good load development and skips the seating depth. Yep! That’s the person I want as my competition.
Everyone do a seating depth test. Do the 100 steps to create a load. Correction do 101 steps.
John, do you thing that the same thing would happend with different calibers or non match guns? 6.5 Creed, 6.5 PRC and yours 7-6.5 PRC have tighter measurments standards that regular calibers, if I'm not wrong.
I enjoy and benefit from observing all of these "seating" test showings on TH-cam, but would really like to see a test preformed by the relation of powder burn rate, pressure increase as seating is deeper, finally in conjunction of bullet ogive. With a knowledgeable and factual formula for this to all having the intention of 2 in 1 hole would benefit a great deal. So; is there any know formula for pressure increase by seating depth, burn rate, bullet ogive out there? I'm all ears and eyes for this one. Thanks for the videos.
I’m happy that I reload knowing that my round will hit the end of a beer can at 100 yards, then hit a pie plate at 500. All knowledge gleaned from reading Lee’s 2nd edition book The mystery of “ controlled” explosion inside of a tuning fork barrel. Read his book
I did not build lowers, I built uppers. 2-300 BO, 2-556's 2-223 Wild. and I bought 2 a 22lr and a 300 Bo Bolt action.
Just subscribed!
Thank you!!
I’d be curious about data regarding ogive style (tangent, secant, hybrid) and how it affects seating depth sensitivity/node size.
Bullets with hybrid profile are less sensitive to seating depth variations. If you're using hybrids here, this may be a reason you don't see signifficant changes
Thanks for sharing. I listen to the hornady podcast kinda pretty much saying same thing. Kinda was confused as a new shooter/reloader
It is significant to notice that the point of impact changed significantly as the barrel heated up and/or the shooter grew more tired. Two factors that sorts the men from the boys in F class shooting.
My seating depth requirements are that it must fit in the magazine and feed correctly. Very simple but it's not for everyone.
I literally just did one today. Closer to lands, horrible. As we got further away from the lands it was much better
I would think if you settled on the number 5 length you would be in pretty good shape. Thank you for all you do and share with us.
Where are those plastic ammo blister packs available at?
They're called Clamtainers
@@FClassJohn LOL! Funny name but thanks the info, I’m going to pick up a couple.
A takeaway is that 6 and 14 are closest to aim point and the same distance from the extremes. Harmonics…
if it was me I would look at the seating depths for shots 3-6 and 17-20,,,
Good content for some sort of testing on a new barrel and 600 yard club matches
You need to redo the test with only shot 6 and 13 loads and see how they score over 20 rounds. ;)
Where did you get that pod lock style lever to replace the round knob for the arbor press?
17,18,19, and 20 look to be petty tight as well.
Looks like 13-20 is in the top half of the target.
I’m sorry what’s a donut?
Thanks for the info!
You bet!
Yes. The answer is yes
Appreciate what you do, but one shot each isn’t even close to a legitimate sample size or even enough to ascertain what the data is. Essentially, you just blew off your spare ammo …at least you got trigger time practice.
Seldom is data in any research the most complete set any scientist or statistician would ideally like to have. But generally, some data is better than none, if only for the purpose of forming hypotheses to be tested. That is why most scientific studies are done iteratively; i.e., some preliminary data is gathered and digested, one or more further hypotheses are developed from that preliminary data, and then further studies of the refined hypotheses are conducted. John is quite explicit about what he's doing and the limitations of his data. I think he did a lot more than blow off spare ammo and get trigger time. I think he shared some potentially very important data for those of us who do not have time to do all the testing (even preliminary testing) and/or who choose not to share the results of testing they do conduct. So: thank you John!
This guys setup is not like your backyard hick ass setup. He has a front rest and thousands of hours of trigger time. One shot is all you need when you know what the fck youre doing Tony.
no but it proved that it didn’t affect this load very much. Had it, you may have seen 3-4 moa spread.
Hornady did a great job covering this
Disagree. He shot a 200-15X with a 92.5 thou seating spread. If you study the target, it looks to ME like he could have used ANY of those seating depths for all 20 rds and would likely have achieved the same score. (15-16 might be a weak spot and is worth a redo for confirmation ).
But imho, no it isn't the end-all-be-all to seating depth but it WAS revealing and interesting food for thought. Also, #3-6 and #17-20 were all X's so.....even ran a 2nd time in reverse order (for barrel temp) doesn't seem like it would have made any difference. It was a damn good score with no two-depths the same. That's crazy.
Good info john
Good stuff
Sounds like a test I need to do in my load workups so I can quit obsessing over that 2-3 thou seating depth. I'm glad you showed those clamtainers! A new thing to buy and try! .... So much work ahead.... 🤔😉😀👍👍
Glad to help
Like your arbor press. Silly question - what are the cartridge boxes your using ? Excellent video ! If I don’t have access to a long shooting location, limited to 100 yards - is testing like this evening meaningful ?
Thats funny. I was thinkin the same thing on the cartridge boxes.
Did you use tuner, because it probably eliminates the difference that comes from the length variation. Or it would be a good testing idea.
My tuner was set to '0' which is my zero point from where I did my load workup. No other tuner settings were used. But it's possible the tuner could possibly overcome any of the group variance if used correctly.
Good vidieo
New hand loader, I liked the video. My question is how does seating depth effect velocity, if at all?
Doesn't really do much in this case. SD was 11.2 across all 20.
Where do you get the plastic shell holders that you have. looks like a good thing.
clamtainer.com