Load work up in a ar10, lr308 Re: pressure ladder

[JiggyIi]

Is this similar to looking for pressure with a bolt rifle? I originally assumed it would be, and figured I'd ask you folks that know these platforms.
I started with H380. Some folks allowed that to be too slow a powder... Well, I reckon it is. 500rds or so, discovered the bolt carrier had cracked.
So, new bolt carrier, and some BL-C2, going to start over.
Start low, roll up slow till flatter primers? That's what I do in a bolt gun......

I run Blc2, Re15, in my DPMS LR 308
26" pipe, 2800' with 165's 168's
Mostly BLC2 Cuz I have a lot of it and the Govt' has used it in 308 forever and Re15, Win 748 are very hard to find
BLC2 also in the 223's

 

[Gregg C]

I run Blc2, Re15, in my DPMS LR 308
26" pipe, 2800' with 165's 168's
Mostly BLC2 Cuz I have a lot of it and the Govt' has used it in 308 forever and Re15, Win 748 are very hard to find
BLC2 also in the 223's

Thanks for that. Availability is kinda why I settled on BLC2. It's nearly always around!

 

[Gregg C]

This is hard I find ARs in 308 show pressure signs early or at least different then bolt guns do. One example of the this is an ejector swipe shows up as soon as you get into moderate pressure, I have seen this with Lapua, standard Lake City, and M118LR brass among others and that is not soft brass.

I don't use adjustable gas blocks on AR-15 but find that they help on large frame, I think the gas port is oversized which provides great reliability with increased wear. Turning the gas down has helped ny builds.

Just my 2 cents,
wade

Thanks. I started out with PPU loaded ammo...it was really hot stuff. I never ran it over my chrono, but had ALOT of feed issues with it. My reloads with H380 were better, but evidently still too hard on the system. I'll watch for swiping. Valuable food for thought on a gas block switch...

 

[budlight]

I can never run gas gun to bolt pressures.

Why not, please explain?

FN SCAR® 20S NRCH I had a friend buy one of these FN's. We tried reloading for it and if you go above Service Rifles reloading tables it would blow primers. So I did a little research and built us both full on bolt gun pressure ar10's. I've popped maybe one primer over the years and it was my fault. When I tried using max loaded 125 grain with TAC and a bunch of range brass and some Military brass has really low case volume. So it was my bad!

 

[ARlife4me]

I can never run gas gun to bolt pressures.

But then again you might not be able to use the same load for your gun in someone else's that is near op in yours.......right! Now try and use a lite weight bcg and see what happens to you load for that AR. It will have signs of op, swipes and blown primers......right! Here's the fix it. Increase dwell time by going heavier on the buffer or heavier bcg and heavier spring (helps some, but not as much as the 1st 2).

True on the not being able to run BA pressures against an AR in most instances.

 

[ARlife4me]

Thanks. I started out with PPU loaded ammo...it was really hot stuff. I never ran it over my chrono, but had ALOT of feed issues with it. My reloads with H380 were better, but evidently still too hard on the system. I'll watch for swiping. Valuable food for thought on a gas block switch...

I've run ppu180 soft points in a rock river 308 with 0 issues on brass, primers or fte/ftf's.

 

[ARlife4me]

I'm working on several 308win loads for AR10/SR308's for bullet weights in 110,125,130,135,150,155,170,180,185 and 190's.

 

[DavidA]

I've done some work on loads for my LR308 with a 20" Black Hole Weaponry P3 barrel. With standard weight buffer and non adjustable gas block. After watching the effects of over gassing and the need to increase dwell time , I opted for an adjustable gas block and a heavier buffer and spring .

 

[kfreeze]

Oh yeah... Rifle length gas tube, carbine buffer( collapsible buttstock) , fixed gas block. Thinking pretty hard about a rifle length buffer, so I could slow the BCG down a little. Like to avoid adjustable gas block, tho, if possible.
I hear some folks talking about Varget,too. That's a bit faster burning yet, and not out of the question.

Don't mess with buffer weights and all of that stuff. Just get yourself a decent click adjustable gas block and save yourself a lot of headaches. That will also stop you from ever running the action too hard again. Anytime you load your own ammo it's much easier to simply adjust the gas block that way. I run them on every ar that I build now, and I never have the problems or spend way to much time messing with buffer weights or springs. All you need to do is adjust the gas block so that the bcg just locks back when fired with an empty mag in it. I go one click after that sometimes if I know the temps will get colder like my coyote ar that gets used all winter. That one piece can save you much time and make your rifle run noticably cleaner if you use a silencer.

 

[ARlife4me]

Don't mess with buffer weights and all of that stuff. Just get yourself a decent click adjustable gas block and save yourself a lot of headaches. That will also stop you from ever running the action too hard again. Anytime you load your own ammo it's much easier to simply adjust the gas block that way. I run them on every ar that I build now, and I never have the problems or spend way to much time messing with buffer weights or springs. All you need to do is adjust the gas block so that the bcg just locks back when fired with an empty mag in it. I go one click after that sometimes if I know the temps will get colder like my coyote ar that gets used all winter. That one piece can save you much time and make your rifle run noticably cleaner if you use a silencer.

I'll say you are correct and a little not so? If you get barrels from the same maker it will be easier on new builds and their setups, but with different makers having gas ports different sizes sometimes it's easier and better to use a heavier buffer (I'd elect to go with a heavier spring). If my math is correct (I'll verify when the A5 tube arrives) that it's 3/4" longer than a standard carbine length buffer tube. The A5 recoil system is designed to use a rifle spring w/4" buffer making impulse lighter? If that's true, then a possibility of doing the same for the AR10 is the same? What it might take is using the AR10 rifle spring and an AR15 carbine buffer (standard AR15 carbine buffer is 3/4" longer than AR10 carbine buffer). Bolt barrier difference between the 10 and 15 platforms are 3/4", so using the A5 tube is a possibility? with an adjustable weighted buffer (2 weights on a 10 and 3 weights on a 15) gives more weight flexibility! I'm going to try this on my 6.5prc and 7saum AR10's. What is hoped for is using a lite weight bcg in leu of a heavier 1? Odin adjustable AR15 buffers come in lite and heavy (body only weights are 1.44 lite & 3.07 heavy) that give a range from (including both styles) ~2.01-7.51ozs. Lite maxes @ 5.88ozs using 3 tungsten and heavy is lightest @ 3.73ozs using 3 aluminum weights.

 

[richhymas]

I am curious what your primary use is for the rifle? My dad and I share a DPMS LR-308 and we started with factory 168 gold medal match, which shot pretty well. We then developed a load that essentially matched the velocity and POI at 100 yards with 165 and 168 bullets which shot very tight groups. Never worked up another load. That bullet did everything we wanted it to out to about 600 yards.

 

[ARlife4me]

I am curious what your primary use is for the rifle? My dad and I share a DPMS LR-308 and we started with factory 168 gold medal match, which shot pretty well. We then developed a load that essentially matched the velocity and POI at 100 yards with 165 and 168 bullets which shot very tight groups. Never worked up another load. That bullet did everything we wanted it to out to about 600 yards.

That makes ir easy then!

 

[kfreeze]

I'll say you are correct and a little not so? If you get barrels from the same maker it will be easier on new builds and their setups, but with different makers having gas ports different sizes sometimes it's easier and better to use a heavier buffer (I'd elect to go with a heavier spring). If my math is correct (I'll verify when the A5 tube arrives) that it's 3/4" longer than a standard carbine length buffer tube. The A5 recoil system is designed to use a rifle spring w/4" buffer making impulse lighter? If that's true, then a possibility of doing the same for the AR10 is the same? What it might take is using the AR10 rifle spring and an AR15 carbine buffer (standard AR15 carbine buffer is 3/4" longer than AR10 carbine buffer). Bolt barrier difference between the 10 and 15 platforms are 3/4", so using the A5 tube is a possibility? with an adjustable weighted buffer (2 weights on a 10 and 3 weights on a 15) gives more weight flexibility! I'm going to try this on my 6.5prc and 7saum AR10's. What is hoped for is using a lite weight bcg in leu of a heavier 1? Odin adjustable AR15 buffers come in lite and heavy (body only weights are 1.44 lite & 3.07 heavy) that give a range from (including both styles) ~2.01-7.51ozs. Lite maxes @ 5.88ozs using 3 tungsten and heavy is lightest @ 3.73ozs using 3 aluminum weights.

I usually use a low mass bcg with my adjustable gas block. And some times I even get the jp silent captured recoil spring and put the lightest spring in it. With the gas system adjusted with the gas block, I can watch bullet impacts at 300 yds on 24x, and I have none of the brass signs of over gassed. Generally the gas ports on barrels are over sized so that they always work. Although, I have had 3 barrels that had to go back to have gas ports opened up. One to x-caliber, one to radical firearms and one to palmetto. Of those, x-caliber was awesome to talk to. They told me since I had an adjustable block and relaoded that they would open it up an extra .010" so that it would work no matter what powder and bullet I ran in it.

 

[meatyrem]

Don't mess with buffer weights and all of that stuff. Just get yourself a decent click adjustable gas block and save yourself a lot of headaches. That will also stop you from ever running the action too hard again. Anytime you load your own ammo it's much easier to simply adjust the gas block that way. I run them on every ar that I build now, and I never have the problems or spend way to much time messing with buffer weights or springs. All you need to do is adjust the gas block so that the bcg just locks back when fired with an empty mag in it. I go one click after that sometimes if I know the temps will get colder like my coyote ar that gets used all winter. That one piece can save you much time and make your rifle run noticably cleaner if you use a silencer.

Is there a good brand for gas blocks or any adjustable GB will work? Palmetto AR-10 20"