The M1icon's safety is kind of stiff anyway. It's a mechanical safety that blocks the hammer, but you may have brand new parts in the trigger group. Do a visual inspection, without disassembling the trigger group, for burrs. Look to see if the safety is binding on the trigger guard too. If it does, you need a new safety as yours is bent. Can't be straightened due to it being hardened steel.
Go here and download the free .pdf manuals. FM-23-5 and TM-9-1275. There are exploded drawings and where to apply grease.
Biggerhammer.net - Miscellaneous Firearms Technical and Training Manuals
Buy a copy of Hatcher's Book of the Garand too. About $30 on Amazon or your local gun shop. Has a trouble shooting chapter that's right out of the TM/FM. Easier to find that rooting through the on-line versions.
Oh and it's 150, 155, 165 grain hunting bullets or 168 or 175 grain match bullet$ with IMR4064(more consistently accurate than the 4895's) . Or Varget or either of the 4895's. None of these powders are the only ones though.