I agree with Brenden about the gas port issue. Best bet is to gt a 22lr conversion.
Brownells sells one that replaces your current bolt with a fully enclosed blowback bolt. Literally all you do is open the gun, pull your 556 bolt & drop in this one. Usually around $200 with 2 or 3 magazines. They run stupid good & are a ton of fun.
And who knows, they may not be available soon