I’m nearly 80 been reloading since 69 and regularly do load development and testing in a very wide range of calibers in custom rifles and this is the most informative and valuable source of relevant information I’ve ever been exposed to. This is a must listen too for every handloader . I can’t wait for the next.
This is the kind of information handloaders really appreciate. I'm just in the beginning phase. This is terrific information!!! So much that I am honestly going to re-see this video a couple more times, it takes me a few go arounds to let it all absorb. Great job explaining what is happening during those few microseconds from trigger pull to bang. Great job by all you guys, you obviously know you field of expertise very well, Hornady is lucky to have you all working there. Thanks again all for a great, informative video.
I've been a reloader for 25 years. Good show folks. It was educational! I picked up new information that changed a couple of pre-concieved notions I had. Thank you!
Definitely some great info here in this tech-dense topic. You described "me" in a few scenarios and I'm rethinking some of my "tried and true" ideas of pressure. Thanks so much for putting this out there!
After reloading for 40 years, this is the most educational video I've watched. It does explain many of the traits I've seen but couldn't determine the cause. Keep the videos coming our way! Thanks.
I’m still new to shooting and reloading. I have to say gentlemen this is a honest and bold podcast. I have to respect you for that. However, I just want to understand how to reload my new rifle. You have turned everything I’ve tried to learn on its head and I feel sick. Interest times and thank you so much. I’ll keep trying to understand what best to do and how to do it. The shooting and reloading community is an amazing place.
Just follow the reloading guide in your loading manual. Follow the data and see what ya rifle likes :) seems like alot of what these gentleman talk about is related to wildcats and custom rifles. Factory rifles are different in that realm due to tolerances. And eventual goal of mine is to get a 300 PRC, 7mm PRC, .308 and .300 win mag. The 300 win mag will probably have a barrel custom cut to be the most optimal with the MK248 Mod 0 loading since that's the only reason I want one and will be going the semi custom route technically with that rifle.
@@jacksonthompson7099 truly Fantastico goal brudder! I don't believe that those actual rounds are Easy Peasy available. I've read of that cartridge under "Battle Notes" of those who served & returned to our beloved America. Safe travels brudder
Very educational. The part at the end about monitoring velocity instead of pressure signs was very helpful. I'm new to reloading, but my velocities are higher than the published values. I trickle-up every load and verify my balance beam scale setting with a digital scale. 6.5 Creedmoor, 140 ELD-Match, 41.1 grains of IMR 4350 should produce 2700 ft/sec. Yet I'm measuring 2740-2760 ft/sec with my MagnetoSpeed in 80F weather. Ashbury Precision Savage 10 with a 24" barrel. My seating depth with the 140 ELD-M results in a COAL of 2.824" -- 0.024" longer than the COAL of factory ammo. P.S. I finally scored some H4350, so my next visit to the range will be using 41.0 to 41.5 grains of H4350.
One thing that can be a headache in reloading is the differences in rifles people have which can leave people out of the loop about a specific load. Barrels tho can also be different to in the tolerances which can make a differnce in accuracy and muzzle velocity. I've noticed with my 18 inch 5.56 AR and my S&W model 29 with a 8 3/8 inch barrel is not whats used in regular load data so im abit in the wild in how it will perform. SAAMI and quickload tho should be the go to sources for what I should be expecting.
I'm watching this like a week now.. 10 minutes Monday, 5 minutes on the afternoon, non on Tuesday and so on and so on... I'm finally through with it... Thank you for your time guy's. :)
Thank you Hornady for putting together this podcast. I really enjoy this type of information thank you so much this is stuff I wish I would have known years ago. Thank you guys I can't wait for the video on external ballistics
Darned, this was a great video. This is one of those “hit the back button and listen to parts of it again and again to make sure I understand type”. The talk about pressure and volume and kind of remind me of like a surfboard and a wave were that surfboard is far ahead of the wave or backup against the wave and the steeper the slope the more pressure
W O W !!! Thank you so much for doing this podcast! I have been reloading for more than 40 years, and I still picked up several bits that I didn't know. And I found several explanations for things I have had happen, but I didn't know the reasons for it. I am looking forward to your next podcast.
Great discussion. Tools like GRT have enabled big leaps in helping with powder choices and understanding internal ballistics. In general terms, I like to have a case full for 100% burn ratio. All my best performing loads are case full or slightly compressed. I think you get more uniform ignition and lower SDs this way. There are some odd pairings too that just work really well like N140 in 308 with heavies like 190 smks and the same powder behind 35 bergers in 204 makes for modest velocities in mid 3000’s but great accuracy. I’ll be paying extra attention for pressure signs and testing all my mv’s from now on as I had no idea ejector marks = 70kpsi + !!😮
Thank you for making this podcast series available. I recently found it lots of great information I really enjoy listening to them. I downloaded the 4 DOF app. After just looking through it quickly it's awesome can't wait to try it out. Thank you and keep up the great work.
Great job guys. I would have loved to get a 300 PRC. But the lack of inventory held me back. I believe it's my dream cartridge. I was pissed about free bore topic, thinking you guys skipping length of free bore on purpose. But great info. Thanks
Loved this conversation/education. I wish a bullet could be stopped untouched right after leaving the barrel by a magnetic field to see and measure if cup and cores deform any different than monothilics like copper. You can do it Hornady!
Absolutely fantastic. Validates what i have seen in I dont know how long, 40 years of reloading. Down loading some Saami specs now too. I just want to fine a little more on bullet searing depth or more specifically ogive to lands distance. . Thank you guys for finally erasing so much of these dangerous myths out there. Now if i can just gget
One topic I would like to hear about is the effect on pressure/resistance/fouling or other issues from having a more aggressive twist rate than standard, same question also for the external ballistics video, what are the negatives of a higher twist rate... thanx
Best discussion of this topic I have ever seen. You didn’t get into the chemistry or thermodynamics of hot reacting gasses. I probably wouldn’t understand the chemistry anyway…. You mentioned reloaders not having a pressure testing device. Many years ago I bought a strain gage setup which I used briefly. I thought I should glue the strain gage over the chamber but the closest I could get it after the threaded portion of the barrel was just past the receiver. From what you said I must have been near the maximum pressure location after all. I never thought I was getting a reliable absolute pressure reading but I could compare my reloads to a factory cartridge. The factory loads that had a sharper recoil did give higher readings so my gages set up seemed valid. I could see the primer pressure and then the main charge ignite. Which I still don’t understand due to the location of my strain gage. I am now reloading 6.5X47 Lapua in. 30” barrel. I have been using H4350 with good results and about the expected velocity. I tried Vithavouri’s maximum recommended load of VVN 540 and got even better velocity and great accuracy. Unfortunately, I am out of VVN540 and can’t find it for sale anywhere. I never go over (depending on which manual) the recommended load. My custom gun doesn’t show pressure signs from inspecting the fired cartridge at the loads I am using but from your discussion I now understate a gun like mine won’t show pressure signs as soon as I might expect from a factory rifle.
Great video. I have always had a concern about firing a. 380 ACP in a 9mm, or a .40cal in a 10mm. I've never done either, but I am far less likely to ever try it, unless I were ridiculously desperate.
I struggled with Physics in college, but I do remember the this one rule; "For every reaction, there is a equal and opposite reaction" The primer falls under this rule.
The advice at the end is all fine and well when there is published SAAMI spec data to go on, but when you're dealing with a wildcat cartridge its right back to trying to interpret the tea leaves of pressure signs.
Hi Seth, I’ve been watching you here and just saw you on Backfire podcast. I like your stuff so far. I really liked your interview with Jim. Jim’s popular (in my opinion) because of his personality as are the Vortex guys. You have to lighten things up a bit and talk about personal experiences and get your guests to do the same. I wish you success with the podcast and keep up the great work.
How do you measure these pressures? Do you drill a hole in to the free bore section of the barrel? But then you'd only get readings after the bullet has fully left the mouth of the case. Do you also drill a hole into the chamber and through the brass case into the volume where the propellant/powder is?
The SAAMI chamber for the 300 Win Mag has no freebore. It just has a funnel that starts at .315" dia. That is what is used in almost all factory guns. As Seth noted, there are a lot of custom reamers that add a tight freebore section, but they are mainly found on custom barrels. The big advantage of the new cartridges like 300 PRC is that they have the more advanced chambers from the factory. FWIW, the 7mm Rem Mag does have a chamber with.section of relatively tight freebore, so it tends to be more accurate.
Great video. Have you guys done much pressure testing with store bought superformance in .308? I was told by Hornady this combo would not work. I have no way to test what actual pressure is but with 35 years of reloading and some carful experimenting I came up with a load that works well for my application. 28” barrel. 175 gr Nosler RDF, federal 210m primers, 49.8 gr powder with lapua brass.
You mentioned pressure signs on a gas gun having to do with timing. PLEASE do an episode on that. I'm running a 16.5" 308/AR with a Trash Panda. Still having issues even after putting the h3 buffer and turning the gas down.
@@mikecross2435 Monoliths are longer due to less density than lead core bullets, and they resist being driven into the rifling more due to their structural integrity. With a gas gun, especially with .308 bore volume and chamber pressure, the port location and diameter, chamber dimensions, and carrier/bolt gas efficiency will all come into play as to how quickly it will begin primary extraction. That can cause primer dropping, blanking, harsh treatment of the case head and rims when the cyclic rate is too fast. Where is your gas port located on the barrel? Some manufacturers use CLGS on 16" .308, which can be a huge contributor to early unlocking/bad timing.
@@mikecross2435 Also, once you attach a suppressor, you effectively increase the dwell time after the bullet passes the gas port because the suppressor acts as an accumulator, effectively lengthening the barrel. That will cause really harsh treatment to the cases during extraction, especially with shorter gas systems. 16" suppressed runs best with Intermediate or Rifle-Length Gas.
I understand what you are saying about Lawyer Loads but could you please provide a brief commentary on why I can look up a load in the Hornady book and the same load on the Hodgdon site and the max loads are materials different
Please do an episode about rifling. 1) Relative width of lands and grooves. 2) Square lands and grooves vs. metford type rifling vs. polygonal. 3) Depth of rifling. eg. 30 calibre with .308 or .311 projectiles. 4) Can blow-past ever be useful or desirable?
How do straight wall cartridges get affected by all this knowledge you're passing on. And thank you for an awesome effort on communicating what's involved in these reloading bullets velocity etc great job guys
Could you address the internal ballistic effects of the shape of the rear of the bullet? Boattail, flat base, rebate. As the pressure pushes on those different angles, what is the effect on obturation, concentricity in free bore, etc? What effect would a series of rebates have?
Great information gentleman. I have a question, what happens if you are getting early pressure where you are getting ejector marks, slight bolt lift, but low velocities? I have a 6.5 prc with a 22in barrel but getting 100-150fps less than expected? Can tight neck tension cause early pressure signs with lower velocity?
Is there anything as helpfull as Propellant Profiles , thats out of print , out there detailing powder particularities ?? This was great info thats no longer available anywhere that i can find .
Handlebar’s mic is a little hot. I was kinda hoping for a bit more technical info. Maybe that’s too much to ask with proprietary R&D and guarded trade secrets. This was fairly elementary.
I was shooting benchrest about 20 years ago in the 100/200 yard nationals and I had a 6 PPC case that didn't have any powder in it. When I pulled the trigger it just clicked so I pulled out the empty case, confused. There was a whisp of smoke present and no bullet in the case. I thought I hadn't removed the last shot so I tried to put in another round, but it wouldn't even begin to chamber because the bullet had been driven into the rifling by the primer on the empty case. Had to tap it out with a cleaning rod, which didn't take much effort, but what an embarrassment and a concentration breaker.
I'd assume that as the barrel gets hot and increases in diameter, the pressure within the shot cycle must drop... not a lot of expansion at ~6.5x10^-6/°F, but it must make a difference. Is this ever a concern, I wonder?
I am thinking the bullet moves and hits the rifling but the bullet is still in the case. The case has already expanded as far as the chamber allows. The internal case neck diameter during total expansion is larger or smaller to the diameter freebore? Perfectly the same sounds best to eliminate changing pressure and decrease movement.
Most modern bullets are quite jump tolerant, so we would recommend seating off the lands. Touching the lands or jamming the bullet in the lands can increase pressure, so if you go that route, make sure your powder charge is lower than max.
Where do you find max velocity for a 6mm creedmoor? Saami only has a 108 listed at 3050 I think. Where would I find max velocity for a 105 so I can find my max load
Short fat cartridge vs long skinny cartridge (all else equal, powder charge, bullet weight). Barrel length effect on speed? I am convinced the short fat cartridge needs less barrel length for same speed, or is less affected by barrel length.
I would love to hear about some of the higher level internal balistics. If that isn't something that you are able to do is there any chance you could give some references for someone who wants to learn more about internal balistics. I have questions about why we don't have Sabots commonly available. They seem to offer so much. A cartridge could easily be straight walled while shooting small diameter bullet possibly at ultra high speed. It seems ideal to get the speed for monolithic bullets. I am a knife maker and am aware of many of the advances in steel. Especially with the entrance of the .277 Fury running at higher pressure it seems like we could have a jump in firearms technology. I like what you guys have done with extrenal work along with your high speed stuff, and I think it would tie in well with a jump of energy density. It seems that it more wear resistant steels were used at least during the first part of the barrel to cut down on throut erosion. Are there any options coming up.
Hopefully yall see this. I want a 7PRC for hunting big things but I want a short barrel like 18”-20” with a can. Good idea or stick to 20+” on the 7prc. Also that was an awesome episode
From a military weapons expert you are partially correct. Crimped primers certainly reduce the chances of a popped primer causing a jam, which is horrible in a combat situation. The other advantage is long term reliability; military cartridges have reduced chances of contamination in order to support sometimes decades long storage.
300 wm is hard to shoot accurately? Interesting because it has been used for long range and military sniper use pretty much since it came out. Yes, the free bore diameter is bigger than the 300 prc but it's not hard to shoot accurately. 1/2 moa is very doable with a quality factory rifle and ammo
Speaking of lawyer loads. Your 308 load data is significantly less than everyone else. So can you explain why different manufacturers are providing significantly different data? It be one thing if it's half grain here or there. But we are talking 2-3 grains difference
Expected more discussion about dynamically controlling burn-rates? 1) If the ideal is uniform acceleration through barrel-length, then ideal burn-rate increases as time-squared? Yet powders are uniform? Raising questions about burn-patterns both within the cartridge and in the barrel? 2) Likewise, twist-rate of barrel lands/grooves? Lands/grooves can be seen as exerting forces on the bullet (from the bullet's perspective), with linear lands/grooves exerting more-and-more force toward the exit-end of the barrel? Wouldn't accuracy be increased with higher twist at the breach-end and less twist at the muzzle-end (to achieve constant angular-force across barrel-length?)?
Love the technical discussions on the podcast please keep these going. I do have a question in your 11th edition published load for 308 Win. 176-180 gr weight bullets for Varget shows max charge of 42.4gr. yet Hodgdon who makes Varget shows a max charge of 45.0gr. why is this? The first instinct is environmental conditions, however knowing that Varget is a temperature stable powder leaves me a bit baffled.
In addition to what LRRPFco52 said, powder can vary lot-to-lot more than you'd think, even the good stuff. Best to buy in bulk whenever possible for the most consistent results.
Not saying that 300 winchester is better nor am I saying 300 prc is better. BUT! atleast I can reload my 300 winchester brass without having to RE-REAM MY BARREL with a CUSTOM REAMER so that my brass doesn't start giving me STICKY EXTRACTION DUE TO TOO TIGHT OF A CHAMBER REAMER DESIGN BY HORNADY!!! HORNADY!!!!!!
I’m nearly 80 been reloading since 69 and regularly do load development and testing in a very wide range of calibers in custom rifles and this is the most informative and valuable source of relevant information I’ve ever been exposed to. This is a must listen too for every handloader . I can’t wait for the next.
This is the kind of information handloaders really appreciate. I'm just in the beginning phase. This is terrific information!!! So much that I am honestly going to re-see this video a couple more times, it takes me a few go arounds to let it all absorb. Great job explaining what is happening during those few microseconds from trigger pull to bang. Great job by all you guys, you obviously know you field of expertise very well, Hornady is lucky to have you all working there. Thanks again all for a great, informative video.
I've been a reloader for 25 years. Good show folks. It was educational! I picked up new information that changed a couple of pre-concieved notions I had. Thank you!
Seriously one of the best podcasts I’ve listened to. I love learning about the technical details of how this stuff works. Thanks guys.
Thank you for the kind words!
Definitely some great info here in this tech-dense topic. You described "me" in a few scenarios and I'm rethinking some of my "tried and true" ideas of pressure. Thanks so much for putting this out there!
After reloading for 40 years, this is the most educational video I've watched. It does explain many of the traits I've seen but couldn't determine the cause. Keep the videos coming our way! Thanks.
Glad you enjoyed it
I’m still new to shooting and reloading. I have to say gentlemen this is a honest and bold podcast. I have to respect you for that. However, I just want to understand how to reload my new rifle. You have turned everything I’ve tried to learn on its head and I feel sick. Interest times and thank you so much. I’ll keep trying to understand what best to do and how to do it. The shooting and reloading community is an amazing place.
Just follow the reloading guide in your loading manual. Follow the data and see what ya rifle likes :) seems like alot of what these gentleman talk about is related to wildcats and custom rifles. Factory rifles are different in that realm due to tolerances.
And eventual goal of mine is to get a 300 PRC, 7mm PRC, .308 and .300 win mag. The 300 win mag will probably have a barrel custom cut to be the most optimal with the MK248 Mod 0 loading since that's the only reason I want one and will be going the semi custom route technically with that rifle.
@@jacksonthompson7099 truly Fantastico goal brudder! I don't believe that those actual rounds are Easy Peasy available. I've read of that cartridge under "Battle Notes" of those who served & returned to our beloved America. Safe travels brudder
Very educational. The part at the end about monitoring velocity instead of pressure signs was very helpful. I'm new to reloading, but my velocities are higher than the published values. I trickle-up every load and verify my balance beam scale setting with a digital scale. 6.5 Creedmoor, 140 ELD-Match, 41.1 grains of IMR 4350 should produce 2700 ft/sec. Yet I'm measuring 2740-2760 ft/sec with my MagnetoSpeed in 80F weather. Ashbury Precision Savage 10 with a 24" barrel. My seating depth with the 140 ELD-M results in a COAL of 2.824" -- 0.024" longer than the COAL of factory ammo.
P.S. I finally scored some H4350, so my next visit to the range will be using 41.0 to 41.5 grains of H4350.
One thing that can be a headache in reloading is the differences in rifles people have which can leave people out of the loop about a specific load. Barrels tho can also be different to in the tolerances which can make a differnce in accuracy and muzzle velocity. I've noticed with my 18 inch 5.56 AR and my S&W model 29 with a 8 3/8 inch barrel is not whats used in regular load data so im abit in the wild in how it will perform. SAAMI and quickload tho should be the go to sources for what I should be expecting.
I'm watching this like a week now.. 10 minutes Monday, 5 minutes on the afternoon, non on Tuesday and so on and so on... I'm finally through with it... Thank you for your time guy's. :)
Thank you Hornady for putting together this podcast. I really enjoy this type of information thank you so much this is stuff I wish I would have known years ago. Thank you guys I can't wait for the video on external ballistics
Thanks for having the podcast. These are great! Thank you!
Thanks for listening
Darned, this was a great video. This is one of those “hit the back button and listen to parts of it again and again to make sure I understand type”. The talk about pressure and volume and kind of remind me of like a surfboard and a wave were that surfboard is far ahead of the wave or backup against the wave and the steeper the slope the more pressure
Really enjoyed this discussion, when you mentioned energy density it helped line up a few things I have been confused about for a while. thank you
W O W !!! Thank you so much for doing this podcast! I have been reloading for more than 40 years, and I still picked up several bits that I didn't know. And I found several explanations for things I have had happen, but I didn't know the reasons for it. I am looking forward to your next podcast.
Great info all the way through, but the last 12 minutes or so are GOLDEN!
Very good format. I am from Germany , reload my bullets with a Hornady LnL
I ve learnt a lot.
Really very interesting and extremely educational. And brought in a very nice way.
Thanks a lot!!
Glad you liked it!
Great stuff and points well taken. So awesome to continue learning in this ever changing world!
This is great content! Easily understood explanations of aspects I haven't thought about before.
Great discussion. Tools like GRT have enabled big leaps in helping with powder choices and understanding internal ballistics. In general terms, I like to have a case full for 100% burn ratio. All my best performing loads are case full or slightly compressed. I think you get more uniform ignition and lower SDs this way. There are some odd pairings too that just work really well like N140 in 308 with heavies like 190 smks and the same powder behind 35 bergers in 204 makes for modest velocities in mid 3000’s but great accuracy.
I’ll be paying extra attention for pressure signs and testing all my mv’s from now on as I had no idea ejector marks = 70kpsi + !!😮
Thank you for making this podcast series available. I recently found it lots of great information I really enjoy listening to them. I downloaded the 4 DOF app. After just looking through it quickly it's awesome can't wait to try it out. Thank you and keep up the great work.
Glad you enjoy it!
This is some of the best info Ive heard yet. Thank you and hoping for more!
Glad it was helpful!
The bore diameter point was phenomenal
Great discussion, guys. I always learn things from your podcasts.
Thanks for listening
Great discussion. Lots of good info.
Great job guys. I would have loved to get a 300 PRC. But the lack of inventory held me back. I believe it's my dream cartridge. I was pissed about free bore topic, thinking you guys skipping length of free bore on purpose. But great info. Thanks
Loved this conversation/education. I wish a bullet could be stopped untouched right after leaving the barrel by a magnetic field to see and measure if cup and cores deform any different than monothilics like copper. You can do it Hornady!
Absolutely fantastic. Validates what i have seen in I dont know how long, 40 years of reloading. Down loading some Saami specs now too. I just want to fine a little more on bullet searing depth or more specifically ogive to lands distance. . Thank you guys for finally erasing so much of these dangerous myths out there. Now if i can just gget
That's ALOT of good info. Can't wait until the external ballistic episode.
Great info! Curious what effects seating depth has on the pressure inside the case or chamber. If anything
It certainly effects chamber pressure. Typically the further away from the lands, the lower the pressure.
Great great video! - Question - how will poor bullet concentricity affect the pressure/precision in the chamber / freebore design etc. ?
Good information for sure. Reloading for an Elk hunt, 300 WinMag, and can better understand the overall cartridge setup and powder selection.
Thanks. I wish you guys produced these videos a year ago.
Excellent. You guys should start a service measuring pressure for common cartridges. I have a few handloads I'd like tested...
One topic I would like to hear about is the effect on pressure/resistance/fouling or other issues from having a more aggressive twist rate than standard, same question also for the external ballistics video, what are the negatives of a higher twist rate... thanx
Best discussion of this topic I have ever seen. You didn’t get into the chemistry or thermodynamics of hot reacting gasses. I probably wouldn’t understand the chemistry anyway…. You mentioned reloaders not having a pressure testing device. Many years ago I bought a strain gage setup which I used briefly. I thought I should glue the strain gage over the chamber but the closest I could get it after the threaded portion of the barrel was just past the receiver. From what you said I must have been near the maximum pressure location after all. I never thought I was getting a reliable absolute pressure reading but I could compare my reloads to a factory cartridge. The factory loads that had a sharper recoil did give higher readings so my gages set up seemed valid. I could see the primer pressure and then the main charge ignite. Which I still don’t understand due to the location of my strain gage. I am now reloading 6.5X47 Lapua in. 30” barrel. I have been using H4350 with good results and about the expected velocity. I tried Vithavouri’s maximum recommended load of VVN 540 and got even better velocity and great accuracy. Unfortunately, I am out of VVN540 and can’t find it for sale anywhere. I never go over (depending on which manual) the recommended load. My custom gun doesn’t show pressure signs from inspecting the fired cartridge at the loads I am using but from your discussion I now understate a gun like mine won’t show pressure signs as soon as I might expect from a factory rifle.
Great video. I have always had a concern about firing a. 380 ACP in a 9mm, or a .40cal in a 10mm. I've never done either, but I am far less likely to ever try it, unless I were ridiculously desperate.
Been looking for this one forever. Don't know why it took this long to show up on my feed.
I struggled with Physics in college, but I do remember the this one rule;
"For every reaction, there is a equal and opposite reaction" The primer falls under this rule.
🤣
Good education, great work guys
The advice at the end is all fine and well when there is published SAAMI spec data to go on, but when you're dealing with a wildcat cartridge its right back to trying to interpret the tea leaves of pressure signs.
Hi Seth, I’ve been watching you here and just saw you on Backfire podcast. I like your stuff so far. I really liked your interview with Jim. Jim’s popular (in my opinion) because of his personality as are the Vortex guys. You have to lighten things up a bit and talk about personal experiences and get your guests to do the same. I wish you success with the podcast and keep up the great work.
How do you measure these pressures? Do you drill a hole in to the free bore section of the barrel? But then you'd only get readings after the bullet has fully left the mouth of the case. Do you also drill a hole into the chamber and through the brass case into the volume where the propellant/powder is?
The SAAMI chamber for the 300 Win Mag has no freebore. It just has a funnel that starts at .315" dia. That is what is used in almost all factory guns. As Seth noted, there are a lot of custom reamers that add a tight freebore section, but they are mainly found on custom barrels. The big advantage of the new cartridges like 300 PRC is that they have the more advanced chambers from the factory. FWIW, the 7mm Rem Mag does have a chamber with.section of relatively tight freebore, so it tends to be more accurate.
Great video. Have you guys done much pressure testing with store bought superformance in .308? I was told by Hornady this combo would not work. I have no way to test what actual pressure is but with 35 years of reloading and some carful experimenting I came up with a load that works well for my application. 28” barrel. 175 gr Nosler RDF, federal 210m primers, 49.8 gr powder with lapua brass.
More great information thanks
Our pleasure!
Great point on velocity correlates with pressure. If your velocity is high, so is your pressure.
You mentioned pressure signs on a gas gun having to do with timing. PLEASE do an episode on that. I'm running a 16.5" 308/AR with a Trash Panda. Still having issues even after putting the h3 buffer and turning the gas down.
What bullets are you shooting? It’s more pronounced with heavier/longer bullets in the AR-10.
@@LRRPFco52 nothing over 168. Mostly 150's and 130's. Definitely worse with monolithic style copper projos.
@@mikecross2435 Monoliths are longer due to less density than lead core bullets, and they resist being driven into the rifling more due to their structural integrity.
With a gas gun, especially with .308 bore volume and chamber pressure, the port location and diameter, chamber dimensions, and carrier/bolt gas efficiency will all come into play as to how quickly it will begin primary extraction.
That can cause primer dropping, blanking, harsh treatment of the case head and rims when the cyclic rate is too fast.
Where is your gas port located on the barrel? Some manufacturers use CLGS on 16" .308, which can be a huge contributor to early unlocking/bad timing.
@@mikecross2435 Also, once you attach a suppressor, you effectively increase the dwell time after the bullet passes the gas port because the suppressor acts as an accumulator, effectively lengthening the barrel.
That will cause really harsh treatment to the cases during extraction, especially with shorter gas systems. 16" suppressed runs best with Intermediate or Rifle-Length Gas.
@@LRRPFco52 Fairly certain it's a rifle length. Center of the GB is 3" from muzzle. It is the POF Revolution DI. Thanks for the response.
I understand what you are saying about Lawyer Loads but could you please provide a brief commentary on why I can look up a load in the Hornady book and the same load on the Hodgdon site and the max loads are materials different
Please do an episode about rifling.
1) Relative width of lands and grooves.
2) Square lands and grooves vs. metford type rifling vs. polygonal.
3) Depth of rifling. eg. 30 calibre with .308 or .311 projectiles.
4) Can blow-past ever be useful or desirable?
How do straight wall cartridges get affected by all this knowledge you're passing on. And thank you for an awesome effort on communicating what's involved in these reloading bullets velocity etc great job guys
I am know the barrel pressure drops when the bullet passes the gas hole in a "gas" gun but what effect does this have in the bullet and speed?
Could you address the internal ballistic effects of the shape of the rear of the bullet? Boattail, flat base, rebate. As the pressure pushes on those different angles, what is the effect on obturation, concentricity in free bore, etc? What effect would a series of rebates have?
Great information gentleman. I have a question, what happens if you are getting early pressure where you are getting ejector marks, slight bolt lift, but low velocities? I have a 6.5 prc with a 22in barrel but getting 100-150fps less than expected? Can tight neck tension cause early pressure signs with lower velocity?
What bullet, powder, and charge weight? Barrel make?
Is there anything as helpfull as Propellant Profiles , thats out of print , out there detailing powder particularities ?? This was great info thats no longer available anywhere that i can find .
Great chat fella’s 👍
Handlebar’s mic is a little hot. I was kinda hoping for a bit more technical info. Maybe that’s too much to ask with proprietary R&D and guarded trade secrets. This was fairly elementary.
I was shooting benchrest about 20 years ago in the 100/200 yard nationals and I had a 6 PPC case that didn't have any powder in it. When I pulled the trigger it just clicked so I pulled out the empty case, confused. There was a whisp of smoke present and no bullet in the case. I thought I hadn't removed the last shot so I tried to put in another round, but it wouldn't even begin to chamber because the bullet had been driven into the rifling by the primer on the empty case. Had to tap it out with a cleaning rod, which didn't take much effort, but what an embarrassment and a concentration breaker.
Does crimping make a measurable difference on pressure/velocity?
I'd assume that as the barrel gets hot and increases in diameter, the pressure within the shot cycle must drop... not a lot of expansion at ~6.5x10^-6/°F, but it must make a difference. Is this ever a concern, I wonder?
Would love to see them do detailed discussions of observed pressures and velocities with a 264 win mag.
How does rifling work? What effect do muzzle devices have?
Great job 👏🏻
I am thinking the bullet moves and hits the rifling but the bullet is still in the case. The case has already expanded as far as the chamber allows. The internal case neck diameter during total expansion is larger or smaller to the diameter freebore? Perfectly the same sounds best to eliminate changing pressure and decrease movement.
Speaking of OEM chamber reamers. My Remington 7400 has a stepped chamber. Maybe the reamer chipped when they were reaming my barrel out.
Loved it
When reloading for accuracy (i.e. 6.5 Creedmoor) should the bullet (Ojib) be against the free bore lands, or allowed to slam in to them❓
Most modern bullets are quite jump tolerant, so we would recommend seating off the lands. Touching the lands or jamming the bullet in the lands can increase pressure, so if you go that route, make sure your powder charge is lower than max.
Where do you find max velocity for a 6mm creedmoor? Saami only has a 108 listed at 3050 I think. Where would I find max velocity for a 105 so I can find my max load
Great bullets ....
What is the concept of gliding metals?
Short fat cartridge vs long skinny cartridge (all else equal, powder charge, bullet weight). Barrel length effect on speed? I am convinced the short fat cartridge needs less barrel length for same speed, or is less affected by barrel length.
I would love to hear about some of the higher level internal balistics. If that isn't something that you are able to do is there any chance you could give some references for someone who wants to learn more about internal balistics.
I have questions about why we don't have Sabots commonly available. They seem to offer so much. A cartridge could easily be straight walled while shooting small diameter bullet possibly at ultra high speed. It seems ideal to get the speed for monolithic bullets.
I am a knife maker and am aware of many of the advances in steel. Especially with the entrance of the .277 Fury running at higher pressure it seems like we could have a jump in firearms technology. I like what you guys have done with extrenal work along with your high speed stuff, and I think it would tie in well with a jump of energy density. It seems that it more wear resistant steels were used at least during the first part of the barrel to cut down on throut erosion.
Are there any options coming up.
Hopefully yall see this. I want a 7PRC for hunting big things but I want a short barrel like 18”-20” with a can. Good idea or stick to 20+” on the 7prc. Also that was an awesome episode
Many of us are running 20" barrels with the 7 PRC
@@hornady Thanks. I appreciate that.
Why coated bullets?
So if I get it right, that's why military ammo have crimped primers? Cause of loose chambers?
From a military weapons expert you are partially correct. Crimped primers certainly reduce the chances of a popped primer causing a jam, which is horrible in a combat situation. The other advantage is long term reliability; military cartridges have reduced chances of contamination in order to support sometimes decades long storage.
I like hornady ammo for my 6.5 grendel.
And i buy hornady shirts.
300 wm is hard to shoot accurately? Interesting because it has been used for long range and military sniper use pretty much since it came out. Yes, the free bore diameter is bigger than the 300 prc but it's not hard to shoot accurately. 1/2 moa is very doable with a quality factory rifle and ammo
Speaking of lawyer loads. Your 308 load data is significantly less than everyone else. So can you explain why different manufacturers are providing significantly different data? It be one thing if it's half grain here or there. But we are talking 2-3 grains difference
I wish someone would come up with a reloading book strictly for semi-auto gas guns with shorter barrels than bolt guns
Expected more discussion about dynamically controlling burn-rates? 1) If the ideal is uniform acceleration through barrel-length, then ideal burn-rate increases as time-squared? Yet powders are uniform? Raising questions about burn-patterns both within the cartridge and in the barrel? 2) Likewise, twist-rate of barrel lands/grooves? Lands/grooves can be seen as exerting forces on the bullet (from the bullet's perspective), with linear lands/grooves exerting more-and-more force toward the exit-end of the barrel? Wouldn't accuracy be increased with higher twist at the breach-end and less twist at the muzzle-end (to achieve constant angular-force across barrel-length?)?
Love the technical discussions on the podcast please keep these going.
I do have a question in your 11th edition published load for 308 Win. 176-180 gr weight bullets for Varget shows max charge of 42.4gr. yet Hodgdon who makes Varget shows a max charge of 45.0gr. why is this?
The first instinct is environmental conditions, however knowing that Varget is a temperature stable powder leaves me a bit baffled.
Could be a difference in what cases they were using between the 2 companies, and how they calibrate their pressure test breeches.
In addition to what LRRPFco52 said, powder can vary lot-to-lot more than you'd think, even the good stuff. Best to buy in bulk whenever possible for the most consistent results.
What ! No unicorn poop?
👍
Make cheaper 6.5 creedmoor ammo
Not saying that 300 winchester is better nor am I saying 300 prc is better. BUT! atleast I can reload my 300 winchester brass without having to RE-REAM MY BARREL with a CUSTOM REAMER so that my brass doesn't start giving me STICKY EXTRACTION DUE TO TOO TIGHT OF A CHAMBER REAMER DESIGN BY HORNADY!!! HORNADY!!!!!!