"Comerical '06 ammo can be used in the garand. The problem is with the bullet weight, heavier bullets hammering the op rod. You keep the loads to 15-180 range you are good to go."
What you don't know about M1 Garands is a lot.
That's a good way to ruin your day - BIG TIME!
Slow burning powder builds too high pressures at the gas port. You can buy a vented gas plug that will allow you to adjust the pressures for whatever Walmart sells but don't try to shoot that stuff in an original gun.