M1 Garand Loads Using 4895, 168 gr Bullets

[slamfire1]

I also was a tad suprised to see my velocities were lower than the reloading manuals stated. 47.0 should yeild 2700 fps according to Sierra but netted me 2560 fps.

-Is it my chronograph?
-Is it my lot of powder?
-Is it my like new HRA barrel?

It could be chronograph misalignment, I doubt it is the powder, and it could be the barrel.

Being off by 50 fps is an insignificant difference. I think with a Normal Distribution 63% of the time the true lot average will be within two standard deviations of the average. Or something like that: find a college kid who accurately remembers his statistics for the correct explaination.

I try to shoot a "reference" load over my chronograph. If velocities are way off, I readjust the chronograph. Instrumentation error is real.

Also, shoot some ball ammo over the chronograph. If it is slower in your barrel than in the books, guess what, its your barrel.

When the Government accepted powder, the Government inspector carried a reference cartridge. The load was calibrated in the Government pressure barrel. He fired the thing in the contractor barrel and measured pressure and velocity. Which of course were different from the Government barrel. He then adjusted the data by the differences.

There are things as fast barrels and slow barrels. If you shoot a "calibrated" cartridge in a barrel and get low velocities, it is my belief that while velocities are less, pressures are not. I also believe that high velocities in a fast barrel means high pressures.

It is lose/lose no matter what you do.

[Bayou]

.....Did the US ever manufacture ammo for the garand that used a 168 gr bullet? If so, what muzzle velocity did it have? Unless something strange pops up, I can just replicate that with an appropriate powder charge.

Does the new production Garand ammo use a 150 or 168 gr bullet? Has anyone measured the performance of the new production ammo?...

FWIW the attached pic from Hornady's website shows some stats on their 168 gr A-Max Garand ammo.

I plan to shoot my Garand for the first time this weekend, weather permitting. I made two clips each of 47.0 gr IMR4895 and 55.0 gr of H4350. Both of these loads use new RP brass, WLR primers, 168 gr Nosler HPBT Match bullets, an OAL of 3.339" and no crimp. I have an adjustable gas plug and I'm hoping the H4350 loads will work out OK as I have plenty of that powder on hand. I made the IMR4895 rounds because I had a little bit of that powder left and I figured it would be good to start off with a traditional load using the stock gas plug to see how the rifle cycles and groups before trying the H4350. I'll be chronying the session so I'll post up a range report next week.

[MEHavey]

Count the "turns" of the gas plug adjustment screw from open to closed before you start the 4350 test firing.

Be sure you open up the adjustment (near) all the way for first shot (it shouldn't function),

Then close half the turns for second shot (it may/may not function)
- If it does, open up a quarter of the turns
- If not, close down a quarter of the turns

Third shot...
- If it functions, open up an 1/8 of the turns
- If it doesn't, close down 1/8 of the turns...

Fourth shot ... adjust open or closed by what amounts to 1/16 of the turns. (You get the pattern.)

By this time you should be there.


.

[Bayou]

Count the "turns" of the gas plug adjustment screw from open to closed before you start the 4350 test firing.

Be sure you open up the adjustment (near) all the way for first shot (it shouldn't function),

Then close half the turns for second shot (it may/may not function)
- If it does, open up a quarter of the turns
- If not, close down a quarter of the turns

Third shot...
- If it functions, open up an 1/8 of the turns
- If it doesn't, close down 1/8 of the turns...

Fourth shot ... adjust open or closed by what amounts to 1/16 of the turns. (You get the pattern.)

By this time you should be there.


.

Thanks, that's pretty much what the instructions that came with the plug said as well

[Sunray]

"...a guy's got to start somewhere...." Yep. That's what loading manuals are for. The Hornady manual has M1 Rifle specific loads, but that's a fairly recent thing. Any manual's 168 grain data will do. If you want a shooting because it's fun load, use 150 grain FMJ bullets and work up a load.
The rifle was desgined to use .30 M1 ammo with a 174.5 grain bullet at 2640fps. Not .30 M1 ammo's 152 grain bullet at 2700fps. In 1940, M2 ammo's MV was raised to 2800fps to match .30 AP's 168 grain bullet ballistics.
"...Did the US ever manufacture ammo for the Garand that used a 168 gr bullet?..." .30 AP at 2800 FPS. Match bullets they weren't.
Relax. Loading for an M1 isn't rocket science. There's no magic load that shoots well out of all rifles. You have to work up the load for any rifle. It just doesn't work that way. The only really important thing is to full length resize every time and watch the case length. If you're going to use match grade bullets, weigh every powder charge too. Match quality ammo requires meticulous loading techniques.
Hodgdon gives 48.0 to 51.2 of IMR4895 and 43.0 to 47.5 of H4695 for 168 grain bullets.
The CCI primers will do nicely, since that's what you have, but you don't need magnum primers(that's all CCI 'milspec' primer sare) for either powder. Magnum primers are for lighting hard to ignite powders and for extreme cold weather shooting. They burn a bit hotter for a bit longer. Don't worry about it. They're what you have.
"...M2 ball is, however, pretty dismal as a long-range target round..." It was never made for target accuracy. It's battle ammo.