308 Win FEDERAL LOADS

The charge weight is easy to find out - pull a bullet and weigh the powder..... ;-})>

The specific powder is another matter altogether. You'll be able to determine the basic geometry (ball vs. tubular/extruded), but the burn rate at best will be a WAG.....
I have also read comments from others much more knowledgaeble than I am that manufacturers typically use non-canister grade powders. In other words, we can't go and buy the exact same powder, since the manufacturers get a batch of a burn rate +- whatever tolerance, probably at a much better price than $40 a pound.

With the charge weight, and the advertised muzzle velocity, you could always lookup those two factors in reputable reloading manuals and narrow down the possibilities to duplicate the load.
 
OldDude said:
The charge weight is easy to find out - pull a bullet and weigh the powder..... ;-})>

The specific powder is another matter altogether. You'll be able to determine the basic geometry (ball vs. tubular/extruded), but the burn rate at best will be a WAG.....
I have also read comments from others much more knowledgaeble than I am that manufacturers typically use non-canister grade powders. In other words, we can't go and buy the exact same powder, since the manufacturers get a batch of a burn rate +- whatever tolerance, probably at a much better price than $40 a pound.

With the charge weight, and the advertised muzzle velocity, you could always lookup those two factors in reputable reloading manuals and narrow down the possibilities to duplicate the load.
Click to expand...

Would haved being a shorter read if you would have just said - I HAVE NO IDEA ! :p Thanks

Cheers RJ
 
I asked the same question myself after I bought a Savage .308, our American military 7.62 long range sniper ammo is contracted out to Federal and not made at Lake City. This ammo had been loaded with RL15 but was too temp sensitive for use in Afghanistan and Iraq and the powder was changed to IMR-4064.

What load duplicates Federal Gold Match w/ Sierra 168gr BTHP in .308
http://forum.accurateshooter.com/threads/what-load-duplicates-federal-gold-match-w-sierra-168gr-bthp-in-308.3866882/



https://en.wikipedia.org/wiki/7.62%C3%9751mm_NATO

Cartridge, Caliber 7.62mm, NATO, Ball, Special, M118LR (United States): 175-grain (11.3 g) 7.62×51mm NATO Match-grade round specifically designed for long-range sniping. It uses a 175-grain (11.3 g) Sierra Match King Hollow Point Boat Tail bullet. Produced at Lake City Army Ammunition Plant. The propellant's noticeable muzzle flash and temperature sensitivity led to the development of the MK 316 MOD 0 for Special Operations use.

Cartridge, Caliber 7.62mm Special Ball, Long Range, MK 316 MOD 0 (United States): A 175-grain (11.3 g) round specifically designed for long-range sniping consisting of Sierra MatchKing Hollow Point Boat Tail projectiles, Federal Cartridge Company match cartridge cases and Gold Medal Match primers. The Propellant has been verified as IMR 4064 (per NSN 1305-01-567-6944 and Federal Cartridge Company Contract/Order Number N0016408DJN28 and has a charge weight per the specs of 41.745-grain (2.7 g).[38]

Below the number to the right of the powder number is the velocity change in fps for each degree of temp change. And you can see IMR-4064 is less temp sensitive than RL15, and Varget is one of the least temp sensitive powders.

33XPgx3.jpg
 
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Pull some, measure velocity. Try 4064, Varget, H4895, W748, Ramshot TAC. Tune charge weighs to match FGGM velocity and see what happens
 
42gr of 4064, or 42.5gr Varget with a 168 will print tight little groups in just about any rifle if accuracy is your goal.
 
I recently deconstructed a Federal GMM 168 grain 308 round. Not sure of the lot # at this time.
I measured just a hair over 40.2 grains of powder.

XfWvng1.png


The powder looked similar to the IMR-4064, however the kernels were notably shorter.
I was getting between 2540 & 2550 fps with the 168 grain GMM Sierra MatchKings.
In the same rifle (Federal GMM brass), I would need closer to 42.0 grains of IMR-4064 to get 165 grain Sierra GameKings (different bullet, different bearing surface, different BC) going that same speed.

jEOS9Zo.jpg


If I was forced to guess what the GMM powder is, I'd sniff around Reloder-15 as ~40.2 grains puts you right above the 2500 fps mark in the Sierra manual.
 
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4064 kernels are random lengths, the powder in the pic above GMM looks like it is very consistent in length and size. Maybe another powder or just precision cut 4064? It does look like R15 too.
At 40.2 gr, that would be in line with lower nodes i have found with 4064/Varget/R15. If you are a believer that nodes are usually 4% of powder dose apart, then 40.2 is 96% of 41.8 (well known node for 4064/308). Quite slow, but very accurate!
 
Hitzy said:
Do they even use commercial grade powder?
Click to expand...

Commercial ammo normally doesn't use canister grade powder. The ammo makers buy a batch of powder within a certain specification range and develop loadings that will all have the same lot number.
When that powder runs out they buy another batch and develop a new load and that powder may be faster or slower but similar to what they used in the previous lot. These powders won't consistently match any canister grade powder like 4064 or 4895, Varget, etc., and the powder and charges will vary between lot numbers.
 
jethunter said:
Commercial ammo normally doesn't use canister grade powder. The ammo makers buy a batch of powder within a certain specification range and develop loadings that will all have the same lot number.
When that powder runs out they buy another batch and develop a new load and that powder may be faster or slower but similar to what they used in the previous lot. These powders won't consistently match any canister grade powder like 4064 or 4895, Varget, etc., and the powder and charges will vary between lot numbers.
Click to expand...

^^This. If you pull the bullets from 2 ammos with different lots#, you could end up with 2 different charges of different powders. The charges will be similar, and the powder burn rates will be similar, but still different.

The reason they use 4064 instead of Varget, RL15 or 4895 is very simple: price. In drums, 4064 is cheaper than the other ones mentionned.
 
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