Re: 22LR Bolt Conversions...
Personally, I think it's mostly hype, after they're broken in.
As far as I can tell, all of the Atchisson bolts are more or less equivalent.
CMMGs ALL get shot before shipping, and MAY be better extracting unfired rounds.And the newest ones have cotterpin retention of the firing pin, rather than a roll pin.
Individual units of all manufacturers may have issues.
Due to numbers produced, Atchissons are the de facto standard, you'd need a smoking deal to get one of the out of production types like Colt, DPMS, Bushmaster, Air Force. There are some advantages of the M-261 as produced by Oly.