A semiautomatic .22 LR detachable rifle originally made for the USAF. The reciever assembly and barrel can be contained in the buttstock and will float on water,though not waterproof.
The reciever and magazine is made of aluminum. It has had various manufacturers since the 60's. It is still in production.
The Armalite AR-7 can be seen in the following films, television series, and anime used by the following actors:
