.22LR AR Uppers

[Lomshek]

I have a buddy that had so-so luck with the CMMG and Black Dog mags. He reports that the M&P mag adapter is a game changer for him and his CMMG conversion.

And in the vein of some win and some lose I've had an original Ciener kit and a stainless CMMG kit that both have run fine (wet) through many an Appleseed (I'm an instructor and loan them out). I've used a half dozen or more Blackdog 27 round mags and they run just as well as the original Ciener mags. Some ammo works better than others for sure but I've had good luck with cheap Federal bulk packs.

Over the years I have done some polishing of the rails, and other parts to slickify it. The few failures to extract I fixed by slightly deepening the extractor groove in the chamber insert so the extractor could grab a little more rim.

As to the original question I'd go with a CMMG upper with S&W mags if available or Blackdog mags if not. I can't keep their designations straight but they've offered one that actuates the bolt hold open feature when the mag is empty and even have a bolt that works with the forward assist for 100% functionality if that's important to you. Their website is less than clear on what options are available so I'd call them to sort out what you want.

Based on the hive's experience with spotty reliability of all kits just plan on having to do some trouble shooting and fiddling.

[Seven_Sicks_Two]

One thing that I'm a little unclear on... It sounds like both the CMMG and the Tac Sol uppers will hold open after the last round, but the bolt will drop as soon as the magazine is removed. It appears that the Boonie Packer mod and a BHO adapter are available for the CMMG that will give me a functional bolt catch. This really has my interest since my goal is to replicate the manual of arms of a "real" AR as closely as possible. Is there anything that can be done to the TacSol for similar functionality?