Currently, I'm using a CMMG Bravo adapter and it's fine for training, but I'd like a dedicated, accurate .22LR upper. I'm finding most are out of stock and have been for some time.
I only have one. It is not a factory upper.
I bought a CMMG Bravo kit a while back, and shot it through two '5.56' barrels. Both were 1:8" twist, however. So, performance was pretty terrible.
Eventually, I tore apart an upper built primarily from garbage parts (some literally came out of a dumpster) and rebuilt with a CMMG 22 LR barrel (and collar) from Joe Bob's.
It had an out of battery event within the first 50 rounds, and I found that nearly all of my aftermarket triggers had hammer springs too stiff for the .22 LR bolt. (It would often eject and feed, without cocking the hammer.)
I added some Bore Buddy parts - including the basic bolt weight and firing pin.
I 3D printed a few parts.
No more OOBs, and fewer issues fully cycling.
Performance was not impressive, initially -- like 6-8 MoA 10-round groups with decent ammo. So, I decided that we needed to "season" the barrel by just shooting the crap out of it with bulk ammo. The son and I have been working on that for 6-8 weeks. It is probably at about 800-900 rounds of mostly Federal Auto Match (bulk), and it has been interesting to watch group size slowly shrink. (No, it has not been cleaned, and doesn't appear to need it yet.)
I haven't had it on paper in the last few weeks, but it is now hitting a 3" steel target at 65 yards about as consistently as our match rifles.
It might turn into a shooter, after all.
One of the bigger lessons learned, for me, was that CMMG magazines are mediocre (and why only stupidly-long 25/30 rounders!?), I need better CAD practices*, and Black Dog Machine steel feed lip magazines are a solid choice.
BDM magazines have given us zero issues, unless ammo-induced (like a bent round, because bulk pack).
*I designed and printed my own 14-round magazine for potential use in NRL22, before BDM had their 15-rounders back in stock. There is a minor error in my rim guide geometry in the feed lips, which is nearly impossible to fix without starting over -- because of my bad practices in CAD.
It works the majority of the time. But a very slightly oversize rim hangs up just enough to take enough inertia out of the bolt to cause a misfeed.
