Friday Gun Trivia for November 9th 2018 The job of a "tunnel rat" in Viet Nam was dangerous and required great bravery and special skills. Tunnel rats used various handguns for these missions. The US issue Colt M1911A1 was the most broadly used firearm along with other weapns If the 45 had to be fired, it almost always mean permanent hearing damage and was done when absolutley nessesary. Hearing protection was not useful because the soldier had to be able to hear eveything while remaining silent Aquired by the Office of Strategic Services, the High Standard .22 LR Model HD semi auto pistols sometimes were used, they had permanently attached silencers with a usable life of about 200 rounds. In some cases the Ruger Mk 1 Target model also saw action.