Go to this link. CMP Forums Scroll down to ASK EACH OTHER, there is a Reloading subsection, there is some very useful information regarding reloading for the M1 Garand. Also, you can register with the forum, log in, and do a search regarding reloading for M1 Garand. If you can secure a copy of the latest Hornady Reloading Manual, there is a section specific to reloading for the M1 Garand.
Hope this helps you.