CMMG Conversion Kit Experience
I went ahead and ordered the CMMG Bravo conversion bolt from Primary Arms, along with their ACSS reticle Holosun red dot, and I also picked up a few of the Black Dog "Sonic X" mags which were on sale at Midway.
I took it to the range today and am happy to report it exceeded my expectations! I fired a couple hundred rounds and had a single light strike with Federal Champion, which went off on the second try. I tried Aguila SV, Aguila HV, Federal bulk, Federal Champion, CCI Mini Mags, everything fed and ejected great and shot decently. CCI and Aguila SV seemed to be tied for most accurate with about 2" or so groups at 50yds, with the other loads all going into 3" 5 shot groups at 50yds.
Given that I was shooting a red dot without the aid of a bench I am sure the kit is capable of slightly better accuracy than the above, and I might pick up a magnifier for it to see if I can do a little better. I also want to try it at 100yds and see if the rounds destabilize. As it is, the accuracy is great for shooting drills out to 50yds. I did some near to far transitions and transition drills, and felt I gained as much as I would have shooting 5.56. Overall I am extremely pleased with the reliability and accuracy of this conversion. If it maintains the same precision out to 100yds I don't think I will even bother to get a 22lr barrel as was my original plan.
The only negative I can see is that I did accidentally dry fire a couple times, which I am sure this kit is not meant to sustain. The bolt stops on the follower when you run the mag dry, and when you remove the mag the bolt goes forward into battery. When seating a new mag my brain thought "AR mag seated, bolt is forward, must be round in chamber" and I proceeded to dry fire instead of racking the bolt. Luckily the firing pin is hitting the "chamber insert" instead of the actual chamber, so it isn't something that can damage the actual barrel.
I do still plan on getting some of the Borebuddy upgrades such as the weight for the bolt and charging handle insert. I originally planned on getting their full upgrade kit which includes a "buffer pressure plug" that pushes the conversion kit into the chamber so it doesn't slop around. Unfortunately my lower (NFA integral folding lower) uses a unique buffer and wouldn't be compatible with that item. Fortunately, there doesn't appear to be any slop whatsoever between the conversion kit and buffer, probably a result of the unique buffer poking a bit farther into the upper receiver. I am guessing the fact the buffer in my lower eliminates this slop contributed to the excellent reliability I experienced.