Thursday, April 22, 2021

A Note From The Civilian Marksmanship Program



Dear CMP Family,

The CMP advises to not use .30/06 ammunition in M1 Garands, 1903s, and 1903A3s that is loaded beyond 50,000 CUP and has a bullet weight more than 172-174gr. These rifles are at least 70 years old and were not designed for max loads and super heavy bullets. Always wear hearing and eye protection when firing an M1 Garand, 1903 and/or 1903A3 rifle.

This warning is an update/addition to the Ammunition section in the Read This First manual enclosed with each rifle shipment (M1 Garand manual-page 6 and M1903 manual-page 10).

Civilian Marksmanship Program

I first saw this at Irons in the Fire

We hashed some of this around a few months back when I posted about my first CMP purchases/Garands. I would just like to say that I am fairly new to the "Garand Experience" and consider myself a novice. I do have friends who are true Garand gurus and they are not advocates of shooting 220 grain Core-Lokt or some other high pressure hunting rounds through a Garand, but most concur that standard hunting ammo can be fired in a well greased serviceable Garand without changing the gas port, etc. and without damage to the rifle. I know there are tons of pro and con information out there pertaining to this subject. Below is very informative video full of factual data and hands on testing. The CMP statement seems to be more of CYA disclaimer (why else would they include bolt guns?). As for me, I'll continue to buy 150 grain ammo designed for the M1 from CMP or other sources as long as it is available. In the event the world goes full Mad Max, I'll shoot what I can find though it. LOL!


  1. Copper

    What about modern PSI???

  2. Many people still do not know that these gas operated service rifles just like the M14 have a gas port pressure specification. The ammo was loaded with specific types of propellant that have a certain burn rate. If you shoot Remington Cor-Lokt or Winchester Power Point ammo and the like thru your M1 or M1a you are damaging the firearm.

    The M1 rifle was spec'd for M1 and M2 ball ammo. The M14 (M1a) was designed for M80 ball ammo. If you want to run hotter ammo you need a Shuster gas Plug, but your Gas Port Pressure may still be too high with the wrong propellant, normally it was IMR-4895 and later for M80 BL-C(2) .

  3. M2 ball was loaded to a nominal 2740 FPS. Garand Gear sells a hollowed out gas plug that allegedly mitigates any overpressure. I have CMP Greek M2 and also I picked up some Prvi Partizan 30-06 150 gr. ball which they advertise as being loaded specifically for M1 Garands.
    The original load was 50.0 grains of IMR 4895 behind a 150 grain flat based bullet.
    Hornady makes one specifically for the 30-06. It has a cannelure that jibes with the case mouth.
    Good luck finding any components nowadays.

    1. I find about 46.0 grains of IMR 4895 to work well with 147 - 150 grain bullets in the M1 rifle. I've also run IMR 4064 in the M1 and the M1A without bending anything, but nowadays I stick to IMR 4895 because that's the powder those guns were built around, allegedly.

      This assuming today's 4895 is the same as it was in the 1930's.........

      The go-to load for the M1A back when that was "the" rifle for competition was 41.5 grains of IMR 4895, plus or minus a little, with a 168-grain Sierra Match King bullet and a G.I. case.

      Smart guys run 125-grain bullets for "short-line" loads out to 300-yards. They're a little less expensive and a lot easier on the shoulder. The Speer 125-grain TNT varmint bullet is a flat-based hollow point and works tolerably well, although the Sierra's tend to group a little better in my guns.

      As far as loads for 1903/03A3/M1917 Enfield, it doesn't hurt to remember that the last 03A3 was assembled in 1945 and the last 1917 in 1918/1919, so it seems foolish to hot-rod those rifles. Being bolt guns, you aren't restricted to IMR 4895 pressure curve and can run slower powders, but inasmuch as running 4895 in all my 30-cal rifles seems to work pretty well, I stick with that so as to simplify things.

  4. The op-rod will fail gloriously with modern ammo. I had to tell that to my niece's husband. That was all that was messed up luckily. He inherited a CMP Rack Grade IH from his grandfather and took it to the range. He called me after the first shot...

  5. "Good luck finding any components nowadays."

    That's for sure.

  6. WWII .30-06 was actually pretty mild stuff compared to how modern hunting ammo in that cartridge is loaded today. IIRC, even machine gun ammo in the same cartridge from that war was too hot for the M1. This 168gr BT ammo would work in the '03, although recoil was considerably more. Even that ammo is somewhat milder than what is loaded for hunting ammo today. The M1 did not have an adjustable pressure port valve, which the M14 did. As other commenters mention, there are retrofit valves out there you can use. I do not know if they adjust shot to shot, or if you have to figure it out with every different loading you come up with. I have heard of M1 receivers being shattered by excessive force on the op rod, although a busted op rod is more common. M1s are not ammo flexible. Accept it.

    1. The Shuster has to be calibrated for different loads, so if you were unfortunate enough to have a big box of .30-06 that have mixed loads you have a problem.
      I don't know if there is an easy way to make a park in that plug for each one once you've figured out the adjustments.

  7. We've shot some modern hunting 150 Grain 30.06 in an an excellent condition Remington 03/A3 with no noticeable effects. A friend of mine loads period correct ammunition and he loaded up several boxes for us so we mostly use that. I've wondered if some of the "reduced recoil' rounds you can get would work for these older rifles. They sure are fun to shoot and have a small connection to the men that carried them in combat.

  8. Be sure to invite Maxine to the party-I doubt she has scheduled anything yet for this weekend.

  9. All this talk about balls and rods gets me fired up!

  10. The Garand was designed around powders that had a slow pressure rise; since WWII there have been a number of powders that are very suitable for .30-06 but have a faster pressure rise, which in some instances. has led to bent op rods; there's a lot of mass in the Garand op rod and bolt, especially in the rear area around the bolt and it takes time to get into motion. There's also an issue with bullet weight in that heavier bullets (>172 grains) have longer "barrel duration" so barrel pressures stay higher longer which can contribute to the op rod problem, not to mention some folks try to get 168 grain velocities from 180 and 190 grain bullets....

    IIRC, IMR 4895 was either what the Garand was designed around, or was developed for the Garand, don't know which, but it seems to be the recommended powder for Garand loads

    1. Correct. From people who are very knowledgeable about M1 rifles and M14/M1a, the RKI crowds states that you should use powder no faster than IMR4895 and no slower than IMR4064. Most people forget about Gas Port Pressure and only look at chamber pressure. Most chamber pressure testing back in the day involved Copper Units of Pressure or CUP not PSI.

      The M1 rifle can be shot with bullets up to 175 grains, 173 was shot for decades with correct powder choices and keeping velocity reasonable. If you want to hot rod buy a bolt gun not a gas gun.

  11. My son has an M1 Garand, and a 1903 Springfield. He reloads for them both. Plus, I think that he has some type of fixture that goes on the barrel to shoot the M1 Garand with blanks, as he used to attend re-enactments. But he is cognizant of the limits on the guns ability to only shoot lower pressure rounds.


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