Slow powders can bend your op rod. The Remington 150 grain factory ammo should be fine. I wouldn't shoot premium ammo in a Garand.
"It is recommended that very slow burning powders and heavy bullets not be used in the Garand. This is an issue especially important to handloaders, as the pressure curve of slower propellants can put too much pressure on the gas piston, bend the operating rod, and adversely affect the Garand's accuracy. The Garand is best used with bullets of about 150 grains weight, as in "Ball, Caliber 30, M2" ammunition."