The 150gr bullet is a great choice in the M1. I would recommend IMR 4064 starting at 41.4gr to a max of 47.2gr. The IMR 4895 starting at 39.6gr to a max load of 47.1gr.
Actual GI ammunition was quite low pressure:
A TEST OF Herter-glass bedding in the M1 rifle.
Dates of Test 29 February to 6 April 1956
Test Conductor: Larry Moore
Section II. C:
The following data were reported by Frankford Arsenal on a test of Cartridge,
Ball, Caliber .30, M2, Lot T-40915 (surveillance test conducted on 29 June 1954),
Velocity 2759 fs
Std. Dev. 23.9 fs
Mean Pressure 43000 psi
MR Accuracy 4.41 in. at 600 yds.
Ex. Vertical 12.6 in.
Ex. Horizontal 9.7 in.
Ex. Spread 13.4 in.
I received a paper copy of this report from a fellow competitor who knew Larry Moore. It is my recollection the pressure and velocity data came out of pressure barrels, therefore the velocity is a bit high compared to actual GI ball ammunition fired in Garands. Powder technology advanced quickly in the late 1930's through WW2. The original specification for the 30-06 had a velocity and pressure limit. As long as the bullet traveled fast enough, provided the gas necessary to operate the action, the 50,000 psia breech pressure requirement almost became a moot point. Breech pressures would always be less. Progressive powder technology produced that velocity at greatly lower pressure than WW1 powders. Weapons in inventory had sight adjustments for the 150 grain bullet and no one was interesting in changing out all the sights out there by changing the velocity. Besides, it is a real advantage to keep pressures down in weapons. We have been lead to believe, in the popular press , that high pressure is desirable, because these guys are selling magnums and other high performance products. I am going to say it is advantageous to keep pressures down and if you can do the same job at less pressure, the fewer problems you will have.
Now I have shot and chronographed many rounds in my Garand. I consider 47.5 grains IMR 4895 a maximum load with a 150 grain bullet. The action is structurally strong enough to hold more pressure, but the gas system will have issues. A bud of mine recently fired Federal American Eagle in his rack grade Garand, (all GI) and he had operating rod dismounts, and his trigger guard unlatched! We convinced him to use the Federal “Garand” ammunition and his rifle stopped malfunctioning.
M1 Garand Rack Grade , Sammy’s rifle
150 gr Sierra Match HPBT 47.5 IMR 4895 CCI#34 WWII weight sorted brass. OAL 3.290"
24 Mar 04 T= 70 ° F
Ave Vel = 2619
Std Dev = 28
ES = 101
Low = 2559
High = 2660
N = 16
M1 Garand Rack Grade, Kurt’s Rifle
150 gr Sierra Match HPBT 47.5 IMR 4895 CCI#34 WWII weight sorted OAL 3.30"
24 Mar 04 T= 70 ° F
Ave Vel = 2630
Std Dev = 33
ES = 109
Low = 2580
High = 2689
N = 16
I was surprised to see just how low the velocity of the 1966 ball ammunition was in a douglas match barrel.
M1 Garand BMR 9633 Douglas Barrel 1:10 twist
150 gr FMJBT 1966 Ball
14 Nov 2011 T= 74 ° F
Ave Vel = 2545
Std Dev = 20
ES = 68
Low = 2513
High = 2581
N = 8
174 FMJBT White Box 1968 NM M72, Headstamp LC67 match, box velocity 2640 fps
14 Nov 2011 T = 74 °F
Ave Vel = 2592
Std Dev = 28
ES = 103
High = 2647
Low = 2544
N = 10
Accurate Arms AA2495 is a copy of IMR 4895 and grain for grain, I have seen any velocities differences worth a hoot in the 30-06. The other GI bullet was a 175 FMJBT. If you keep your velocities less than or equal to 2640 fps with a 175 bullet, you won’t have any issues. I shot literally tens of thousand of 168 match bullets, and data with AA2495, IMR 4895, and IMR 4064 are below. Do not exceed these loads. However, cutting them a grain or two won’t hurt a thing.
M1 Garand Douglas Barrel 1:10 twist
168 Sierra Match 47.0 grs AA2495 wtd WLR FC Cases OAL 3.30"
5 May 00 T = 82 ° F
Ave Vel = 2632
Std Dev = 16
ES = 50
Low = 2616
High = 2666
N = 10
168 gr Sierra Match 47.0 AA2520 WWII cases WLR OAL 3.30"
5 May 00 T = 82 ° F
Ave Vel = 2658
Std Dev = 35
ES = 85
Low = 2612
High = 2697
N = 5
168 gr Sierra Match 48.0 IMR 4064 wtd LC66NM WLR OAL 3.30"
5 May 00 T = 82 ° F
Ave Vel = 2594
Std Dev = 18
ES = 38
Low = 2575
High = 2613
N = 5
168 gr Sierra Match 49.0 wtd IMR 4064 LC66NM WLR OAL 3.30"
5 May 00 T = 82 ° F
Ave Vel = 2669
Std Dev = 27
ES = 65
Low = 2651
High = 2716
N = 5
175 Sierra Match 47.0 grs AA2495 wtd CCI 34 R-P Cases OAL 3.30"
5 May 00 T = 82 ° F
Ave Vel = 2631
Std Dev = 8
ES = 23
Low = 2617
High = 2640
N = 5
