This is surely a dumb question, but I was watching a youtube video where a guy had an M1 Garand that the action locked back on an empty gun, then closed itself when he inserted the 8 round ammo clip.  I bought a service grade Springfield M1 from CMP probably 8 years ago, played around with it but never shot it, and let it live in the safe since then.  My action never stayed open on its own, it always wanted to ride forward automatically no matter how far I pulled it back.  I'm sure I'm doing something something wrong, but what am I doing wrong?  On the off chance that something is wrong with my gun, what could it be?  Please forgive my ignorance, I know nothing about the M1, I just always wanted one because I'm pure blooded American and because I can.

Google is your friend!

Something is wrong or your not getting it far enough back. There is good videos on how the action works. You can pull it out of the stock and look and see what is happening or not when you pull it back. The operating rod and catch have obvious hooks to hold the bolt back. Typically is is a worn or bent parts causing problems.