Check out the Taccom reliability kit. It is the best thing I have bought for my dedicated .22 upper. It comes with the plug clandestine is talking about. It's well worth the money. Mine will eat just about anything.
http://www.taccom3g.com/22RF_RELIABILITY_KIT.html
Does anyone have any experience with modified uzi mags for a 9mm AR? I have looked into modifying them. It doesn't look to hard has anyone done the conversion?
I have noticed quite a few different company selling uppers with YHM rails at an affordable price. It is kinda strange.
MAS defense
Radical firearms
Hardened arms