Thanks for the info!
I restrained from getting the conversion bolts because I didn't want lead deposits in my SR15 gas tube. Were it a cheaper upper I'd get a bolt too.
They don't result in leading in the gas tube. The .22 might lead up the barrel faster and blowback more powder residue but that's the extent of the situation and minor if you clean reasonably and run .223 in between .22 sessions.
Maintenance effort is actually less than using two uppers in my experience and the accuracy is adequate for many applications. I compete in Steel Challenge with my conversion bolt.
I had the conversion bolt prior to getting the CMMG upper. It functioned very well, but cleaning was a chore (I don't particularly like cleaning guns). The bolt conversion was minute of pop can accurate at 25 yards at best (in my 10.5" LMT upper). The CMMG upper (9.8" barrel) is minute of golf ball accurate at 25 yards or better. I still have not grouped it at 25 yds, but will post results as soon as I do.
The upper I got comes with the stainless unit. Will condition it with fireclean. What ammo have you had the best luck with? I hope they aren't finicky and only eat minimags..
M&p 15-22 hands down



























