I assume you are from CA? I don't know if the .22 LR complete rifles use standard lowers or not, I know you can use a .22 LR upper on a standard lower but these .22 LR ARs being built sold by Colt... I know nothing about their lowers. I am pretty sure though that they do not have a recoil buffer or buffer spring in the receiver extension, so you certainly could not use a standard AR upper on them unless you added a buffer and spring, which if it is that easy I doubt they would be allowed in CA.Is it possible to use another caliber upper on a 22lR lower? Also if the lower is marked as 22 lR only, is it correct that a bullet button is not required?