h4350 is going to be a little slow for the garand in my opinion. the op rod my not like that choice. i ran into the same problem as almost nobody wants to give load data for a garand because of bent op rods. the best thing i could recommend is getting the hornady loading manual as they list gas gun loads for there bullets. if i didn't have a bunch of pain killers in me i'd go find my manual. about 47 grains max of H or imr-4895 varget or bl-c2 or reloader 15 will put you about 2550-2650 fps with the right burn rate of powder. obviously not up to what the 30-06 is capable of but what the awesome m-1 was designed for and not breaking. I'd be much more concerned about the health of my gun than velocity. I just happen to love M-1's. Please do you're research though because as always reloading can be dangerous when going beyond what the gun was designed for. Also i don't mean the gun will blow up as the action is very strong but a broken gun sucks especially when its an m-1