.358,

I would not suggest any of the 4350s for a gas operated action. The federal arsenals, Lake City in particular, used H-4895 for the M-1 Garand rifles. Using it in both standard ammo and their match ammo. If I'm not mistaken, this is the powder Bruce Hodgdon started selling as a surplus powder after WWII. I used it for military matches when I was still shooting matches as a civilian.

Several of my friends who still shoot military matches with the M1A swear by Varget. I hope that this is of some help. Good luck and God Bless.