That New 308 WIN and IMR 4895!

I have thousands of Federal GMM large magnum primers that I purchased just as this "covid thing" hit. I have not used them in 308 Winchester yet, but I plan to next year. I was wondering how I should start my load workup? My current best group size is 1/2 moa. Rifle is a DPMS AR10 that was gutted and all parts replaced with the following: silent capture buffer system, Aero Precision BCG, CMC 2+3 trigger, palm swell grip, Black Hole Weaponry tri-polygonal 24" custom fluted barrel, PSA low profile gas block, Heartbreaker muzzle brake, Valdada Anvil bipod, 40mm V-Tac 20moa cantilever mount, and a Valdada Recon G2 optic in moa. Load is: Peterson Cartridge 308 large primer match brass, Federal GMM large primer, 44.2 grs. of Varget, Cutting-Edge 168gr MTAC projectile.
 
baldhunter said:
Yeah I hear y'all.Seems like everytime there is an election year things start getting scarce.This covid crap really made things worse.I switched to using magnum primers on my 308 Wins,338-06 and 30-06s'.Not because I was looking for more velocity,but because I have a bunch of magnum rifles.Now I just buy magnums for everything.It sure makes it easier.I could have bought some Federal Large Rifle primers last week for $3.99 a hundred.I just left them on the self.As scarce as things have been lately,I figured somebody could use them more than me.I'm just really glad to have what I have,but I've been working on it for a number of years too.
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I can identify with your plight. I used to buy 500 primers from one lot to avoid requalifing loads. I just found a brick of cci 200 primers. I will be using these in place of Fed 210m and Win WRL for some of my loads. Also what load do you use for your 338-06?
 
katakenm said:
I have thousands of Federal GMM large magnum primers that I purchased just as this "covid thing" hit. I have not used them in 308 Winchester yet, but I plan to next year. I was wondering how I should start my load workup? My current best group size is 1/2 moa. Rifle is a DPMS AR10 that was gutted and all parts replaced with the following: silent capture buffer system, Aero Precision BCG, CMC 2+3 trigger, palm swell grip, Black Hole Weaponry tri-polygonal 24" custom fluted barrel, PSA low profile gas block, Heartbreaker muzzle brake, Valdada Anvil bipod, 40mm V-Tac 20moa cantilever mount, and a Valdada Recon G2 optic in moa. Load is: Peterson Cartridge 308 large primer match brass, Federal GMM large primer, 44.2 grs. of Varget, Cutting-Edge 168gr MTAC projectile.
Click to expand...
I would back off a grain and start there. What length gas system you have? Midlength or Rifle Length? I have an 18" midlength Aero M5 build with adjustable gas block (Superlative Arms), but I have my gas block maxed out open vent, or I get ejector smears. I was thinking about going with a rifle length barrel, possibly 20".
 
xsn10s said:
Cabin Fever Reaction GIF
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Perfect! Lol
 
BFD Guns said:
Not one to jump on new things, but I got a rifle chambered 308 Winchester and trying the new IMR powder IMR 4895. I might be the first for load development, so here goes:

18" Aero M5 gas gun with adjustable gas block

168gr Amax w/IMR 4895:

43gr gave a sizzling 2565fps with a 10 SD (Far exceeding the 6.5 PRC in my book)

155gr Amax w/IMR 4895:

44gr scorched earth at 2600fps with 8 SD (28 Nosler got nothing on this)

165 TSX BT w/IMR 4895

43gr lit the atmosphere on fire with 2545fps 13 SD (Lots faster than the 7mm Rem Mag)

Great accuracy and just as good as the 30-06!
Click to expand...
IMR 4895 is not new, was listed as one of the accuracy loads for 308 Win. in my first (Lyman 45th addition reloading manual, has also been used in 30-06 match ammunition since WW II.
 
BFD Guns said:
I would back off a grain and start there. What length gas system you have? Midlength or Rifle Length? I have an 18" midlength Aero M5 build with adjustable gas block (Superlative Arms), but I have my gas block maxed out open vent, or I get ejector smears. I was thinking about going with a rifle length barrel, possibly 20".
Click to expand...
Thanks for the advice. I have been told that a few times.

I have a rifle length gas system. I have the gas block tuned for two clicks above when the bcg just about starts to not eject properly. It is about 70% open.

I went with the 24" barrel for as much velocity as I could get instead of having to use a max load of powder to achieve the highest velocity. When I go hotter with more powder I fall off my accuracy node. I don't mind the 24" barrel because the AR10 is a bench gun and also a prone gun for long distance shooting. I I love the Valdada Anvil bipod, it shrunk my groups about a 1/4" to where they are now. Don't get me wrong... I don't shoot 1/2" groups all day or every day. But I can under perfect weather conditions get them extremely tight. Someone told me that I couldn't get 1" groups out of an AR10 so I set out to prove them wrong. My girlfriend shoots the rig more than I do and she has better results more often than me. I now am focused on the RPR in 338LM.

I am a 100% service connected disabled veteran, I have had seven back surgeries, so I don't "run and gun" anymore. I'm lucky if I can walk to the bench.
 
Last edited:
Mark37082 said:
You really like to stir the pot and attract confrontation. I still enjoy shooting the 308 and can use so many powders that I can wear out a barrel just load testing. If i could only only find more primers, I probably will do just that. If I need to light the atmosphere on fire, I will pull a different gun out of the safe.
Click to expand...
What part of Tennessee are you in? I know where you can get some primers in North Alabama if it's not too far for you to travel.
 
BFD Guns said:
Not one to jump on new things, but I got a rifle chambered 308 Winchester and trying the new IMR powder IMR 4895. I might be the first for load development, so here goes:

18" Aero M5 gas gun with adjustable gas block

168gr Amax w/IMR 4895:

43gr gave a sizzling 2565fps with a 10 SD (Far exceeding the 6.5 PRC in my book)

155gr Amax w/IMR 4895:

44gr scorched earth at 2600fps with 8 SD (28 Nosler got nothing on this)

165 TSX BT w/IMR 4895

43gr lit the atmosphere on fire with 2545fps 13 SD (Lots faster than the 7mm Rem Mag)

Great accuracy and just as good as the 30-06!
Click to expand...
IMR 4895 is hardly new, it is listed as one of the accuracy loads in my first(Lyman 45th addition) reloading manual, it was used by the military for ball ammunition and match ammunition since WWII, I have several pounds of military surplus IMR 4895 powder.
 
baldhunter said:
Yeah I hear y'all.Seems like everytime there is an election year things start getting scarce.This covid crap really made things worse.I switched to using magnum primers on my 308 Wins,338-06 and 30-06s'.Not because I was looking for more velocity,but because I have a bunch of magnum rifles.Now I just buy magnums for everything.It sure makes it easier.I could have bought some Federal Large Rifle primers last week for $3.99 a hundred.I just left them on the self.As scarce as things have been lately,I figured somebody could use them more than me.I'm just really glad to have what I have,but I've been working on it for a number of years too.
Click to expand...
Same problem. Had to back the powder off a little and check with the chronograph
 
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