M-1 Garands require a specific type of powder to work well in reloads. The wrong type of powder can result in a bent operating rod. The Speer Reloading Manual #14 specifically lists 3 powders that are good for the Garand. H414 is not one of them. Be careful reloading for the semi-auto Garand. This manual suggests three powders, H380, IMR 4895, and IMR 4064. I would pick one of those and work up a load.