Congratulations on your new M1.
The operating rod is the weak link. Ammunition that generates high pressure at the gas port will cause damage to the operating rod.
Most current 30-06 hunting ammunition is not safe for use in the Garand due to the op rod. The ammunition can be used when the gas plug is replaced a pressure relieving plug. There are two that I know of, the Shuster (spelling?) and McCann (I think).
Hornady and Federal make Garand safe ammunition. The boxes are labeled as such.
Powders safe for the Garand are limited. I use H4895, IMR4895, and Varget. There are a few others. The Hornady loading manual has Garand safe load chapter. There are some sites on the internet with reputable data. Go look at the CMP forum for a wealth of Garand reloading and general information.
http://forums.thecmp.org/index.php
Generally, bullets are limited to 150 to 180 grains. There are some folks that use bullets lighter than 150 grains. I am dabbling with 110 grain bullets. For 100-200 yard matches, the recoil is reduced and the ballistics of the smaller bullets is not a factor.
Not sure about anyone using heavier than 180 grain bullets.
Full length size your brass. If the cases were fired in another rifle, you may want/need to small base size the cases first, but generally that will not be necessary. Cases fired in your rifle will not need small base resizing.
CMP Greek surplus HXP ammunition is a good source of cases. The ammunition costs about what factory new empty cases cost and you get to "unload" them in the bargain.
Enjoy your rifle