Garands were designed around IMR 4895. Powders with a significantly slower burn rate (slower than 4064, as noted above) may damage your op rod & rifle. Any powder with a burning rate similar to IMR 4895 can be used. Alternates include H 4895, Varget, AA 2495 and others.
The 168 gr bullets often give superior accuracy in most Grands. Wideners sell the Prvi 168 gr BTHP bullet (gives me sub-MOA accuracy in a bolt action) http://www.wideners.com/itemview.cfm...ir=278|281|727