I have the CMMG 'India' 22 conversion kit for my Daniel Defense DDM4 V2.
It has been 100% and sccuracy is very good as well. I prefer this method because I get to keep the same trigger/optics/rail/stock/etc as my primary rifle... and can practice for much cheaper. Blow through 1 mag of 5.56 after shooting as much .22 as I want to blow out the gas tube and such...
Works great. I don't know if mine is so reliable because I got the complete kit or not... if I had it to do over again, I would probably buy the cheaper, basic conversion kit... but I'm very happy with mine.
Glock 17 G4 FDE | S&W M&P 22 | Sig P226 MK25 | Sig P229 Extreme | HK P30 | HK45 | HK USP | HK USP Compact | HK USP 45 TACTICAL | XDM 45 Compact | XDM 9
Daniel Defense DDM4 V4 | Arsenal SGL 21 | ASA SBR w/ Side Charger | Savage Mark II FV-SR | PSA M4 clone
Mossberg 590A1 20" SP | Mossberg 500 Cruiser