Garand with a heavy bullet question

[Joe Portale]

Hope that someone can clear up something for me. What is the heaviest bullet that can be safely used in a M1 Garand? I have seen/read that nothing over 175 should be used, then I see 1000 yard shooter using 200+ grain bullets. The heavier bullet is a definite advantage out to 1000 yards, but what good will these bullet be if they tear the op rod out of the rifle?

Thanks.

 

[Art Eatman]

It's not the bullet weight, but the type and charge of powder. The rifle is designed to operate with a pressure of around 2,000 psi remaining at the gas port.

As I understand it, powders which burn more slowly than 4895 CAN have higher pressures there, depending on the charge--particularly if near maximum breech/chamber pressure.

So, if you're at the 47,000 psi chamber pressure with 4895, it shouldn't adversely affect the operating rod. With a 200-grain bullet, this will be less powder than for a 150-grain bullet.

FWIW, Art