You have the Rifle or Carbine?
Handy firearm, is the SN just numbers of has a "alpha" charater in front?
The "alpha"means a post 64 firearm
Get two new magazines for it.
I have two and have bedded the gas-block and then the backside of the stock ferrule where the barrel tendon is, this allow my rifles to group rounds inside the "X-ring" of standard 200 yd center.
Brownells has replacement gas pistons for them.
Enjoy it!