A 12 GA shotgun with slugs or buck has much more recoil.
Your Garand was designed in 1936 and issued with ammunition that by today's standards was pretty mild. Pressures were in the 40,000 pound range, never to exceed 50,000 psi. The rifle runs well when are shooting 150 grain bullets around 2700 fps. The action is strong but gas port pressures limit both the bullet weight you can use and ammunition pressures. If you use bullet weights above 180 grain and modern "magnum" cartridges it is likely the action will open up too quickly, tear rims, eject cartridges a million miles, overide ammunition, and induce a permanent bend in the operating rod.
Do not drop rounds in the chamber and drop the bolt on them. This rifle has a free floating firing pin and modern commercial ammunition has very sensitive primers. A primer might go off. If it goes off with the lugs engaged you will get a divot in the ground. If it goes off with the lugs out of battery, you may blow the back of the receiver off.
If you do not purchase a SLED, single loading device, then feed from the clip or lower the bolt half way before dropping it on the round. Also, bump the op rod to ensure the lugs are engaged.
I recommend putting antiseize grease on the gas plug. The sucker will carbonize up and be difficult to remove.
Clean the gas system without taking the gas cylinder off the rifle, that front sight is attached to the gas cylinder, which is splined on the barrel. Knocking it off each time just creates wobble. Keep your chamber clean, use an artist brush to paint on grease on the locking lugs, operating rod bolt cam, the notch on the underside rear of the bolt, and just grease anything that shows rubbing.
Check out the CSP page for lots more Garand Information
http://www.jouster.com/. Lots of people shoot these rifles and there is lots of information on them.