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What's safeWhat works best?

1435 Views 5 Replies 4 Participants Last post by  KING
I'm more than just a little concerned regarding some widely divergent loading data. I'm loading match brass, Accurate 4064 powder and Nosler J4 Competition 168gr. hpbt bullets.

This data is for the same 168 grain hpbt bullet. suggested Max load of 43.0 grains of 4064=2571 fps (24" barrel)

Accurate 2001 Reloaders Guide . . . Max load 42.5 grains of 4064=2601 fps (24" barrel)

Sierra lists 44.7 grains of 4064=2700 fps
Sierra also lists 41.4 grains=2500 fps as an "accuracy" load.

Lyman's 46th edition . . . 45.0 grains of 4064=2717 fps (26" barrel) as "potentially most accurate load" :sniper:

Anyone out there as confused as I am?
So what's safe in my NM M1A?
Anyone load any of this Accurate 4064 under a 168 gr. hpbt?
If so, how much is safe? And what load was most accurate?
I'd appreciate any and all the help I can get.
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When loading for the M1A, you have to take some of the loading data with a grain of salt. Some of the "accuracy" loads they list are high speed rds for bolt guns, which just won't fly with a gas operated gun.

Based on my experimentation with 4064 with 150gr FMJs, I would have to say that a load between 43 & 44gr for your 168 J4s should be in the ballpark. Of course, this also depends on what cases you are using. Military cases, like Lake City, are thicker-walled and take less powder than standard Winchester, Remington, etc cases. The 43 to 44gr would be for military cases - for commercial cases, I would start around 43.5 and work up as far as 45gr. And this is using the military match standard 2.830 OAL.

You are correct in the fact that 2.800" is the recommended Saami maximum OAL for .308 rounds. There is, however, benefit in seating closer to the lands in most all cases. For the M1A, the size of the magazine is your limiting factor. The 2.830" OAL is about the max length that a M1A magazine will feed reliably - plus, it is also the NATO standard for Match rounds. According to their spec, you are looking for a MV of 2550fps, and a chamber pressure of 50,000psi.

They also spec an overall loaded cartridge weight of 385gr - but that is for IMR 4895 powder.........typically you'll need a little more 4064 that 4895 - about a grain or so. If you have a scale that goes that high, this weight figure might make an interesting comparison to how your loaded test rounds fire.
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