My MechTech CCU is giving me a headache. I have two major issues going on;
1 - It has failure to fire malfunctions with anything more than 7-8 rounds in the magazine. I'm still diagnosing the why but the what is pretty clear, the disconnector is somehow hanging up... first round fires, the bolt cycles, strips the next cartridge and gets it into the chamber no problem, hammer is cocked, safeties in fire position, ease finger forward for reset.... nothing. I have to run the bolt, ejecting a perfectly fine cartridge, to get it to fire again, and then it FTFs again. I get every other shot until there's 7-8 left and it runs like a top.
This is more likely an issue with the frame than it is the CCU though; I need to do two things for "proper" troubleshooting... I need to borrow another frame for a bit, either another double stack or a single with an extra strong spring, and I need to remember to dig the original slide and magazine for the RIA frame and shoot it as a pistol.
2 - the base level stock is downright damned uncomfortable for me. By all means, spring for either the extending stock or the AR collapsible stock adapter, I'll be getting one of either shortly, or making something custom for myself. It looks easy enough to do...