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AR-7 http://en.wikipedia.org/wiki/AR-7

The ArmaLite AR-7, designed by Eugene Stoner, is the civilian-commercial version of a rifle adopted by the US Air Force as a pilot and aircrew survival weapon. Its main market is as a knockabout rifle for carrying in a backpack, car trunk or pickup truck.....The AR-7 is chambered for the .22 Long Rifle cartridge.....

AR-5 http://en.wikipedia.org/wiki/AR-5

The AR-5 was the basis of the MA-1 aircrew survival rifle, adopted by the USAF in 1956, as a replacement for the M6 Aircrew Survival Weapon, a superposed ("over-under") combination weapon which has a rifle barrel over a .410 shotgun barrel. While there is an advantage to such a combination, the AR-5 had the advantage of rapid fire, using the same .22 Hornet cartridge used in the M6. ......

I stand corrected

LT--
Don't know if this info will help or not. Back in the late 70's, the Army Reserve unit I was in did our familiarization fire using our unit's M-16s, .22 conversion kits checked out (from Training and Audiovisual Support, if I remember right), and .22 LR ammo. Did all our firing on an indoor range in one of the buildings in the 600 numbers on Fort Sam Houston. We were on a two year cycle--familiarization one year and qualification the next--and I think we had to use .22 LR that year because .223 was in short supply, but boatloads of .22 LR was available. Wish I could remember distance (think it was 25 yards) and type of targets--the memory is one of the first things to go. Or is it the knees? I forget which.