My Guard unit (CT) had some .22 conversion kits in the armory for the M-16s. We used them once. There is also a yearly rifle match at the Coast Guard Academy that CT NG guys go to. The match uses service rifles with the .22 conversions.
Way back when, I shot .22 bolt action rifles while on my high school rifle team, we used rifles belonging to the NG unit in the Ansonia armory. They also had a range in the basement.
Every armory I was assigned to had a range inside (Waterbury, Naugatuck, New Haven, and the above mentioned Ansonia armories- the Danbury one had one also though I wasn't assigned to that one). Most of them were decomissioned when I joined, but obvious there was a need for a range capable of handling .22 cal shooting at one time.
I know 1st Mar Div had a rimfire rifle team back in the 70s. They used Marine Corps rifles.