MacCool

I'm a believer in purpose-built weapons, so I didn't want to screw around with conversions. .22 conversions can be problematic under the best of circumstances and I suspect that such a conversion on a piston upper will only be more so...sort of a double compromise in intended function. While some conversion kits work more reliably than others, many or most of them are kind of a kludge with a series of workarounds that represent compromises in design and function. Besides, if I spot a critter out in the yard that I need to shoot (muskrats come to mind), I didn't want to grab a rifle and then have to convert it on the spot to a .22 so I don't have any 5.56 rounds flying around the neighborhood or across the lake. My approach was to just buy a dedicated .22 in AR style. IMHO, state of the art there are the Colt .22's at Colt .22 Tactical Rimfire | M4 & M16 Rimfire Rifles | Powerful & Cost Efficient. They're made by Walther and are very well-made. Although they definitely prefer the higher-velocity rimfire ammo, mine has been very reliable and very accurate.