This is an excellent example of a fairly rare Model 6 Police submachine gun chambered in .45 ACP. This model was designed and patented by Gordon Ingram in 1949 and was produced by the Police Ordnance Company (POC) circa 1951. This model was probably one of the best post-war selling machine guns, as it had a unique design and was brand new in 45 ACP. It was purchased by a few police departments in the early 1950s and most sales were made to South America and the Far East. The POC was a limited partnership established by four WWII combat veterans, with Ingram as the chief/head engineer. The unique design of this model has what's called/patented a "Progressive Trigger" mechanism. This design allows the firer to pull the trigger half way back for semi-automatic fire and all the way back for full-automatic fire without having to change the selector settings. Ingram left the company in 1952 and in the late 1960s is credited with designing/developing and producing the very successful MAC-10 and MAC-11 SMGs. Although this weapon is similar in outward appearance to the Thompson submachine gun, it is very different internally in that it uses a machine bolt and barrel assembly with all the rest of the components being made from stamped sheet metal parts including the receiver similar to the MP40 and STEN submachine guns. It fired from an open bolt in a simple blow back manner with a fixed firing pin and the noted 2-stage "progressive" trigger. The chamber is marked "INGRAM PATENTS PENDING/POLICE ORDNANCE COMPANY/LOS ANGELES CALIF. U.S.A./M6 MILITARY CAL. .45 A.C.P." It has standard blade front and simple windage adjustable rear sights. It has a two-piece pistol grip/stock assembly with a horizontal forend. It is complete with one stick magazine and a canvas sling.