The FP-45 Liberator was a .45 pistol designed for resistance in Europe during WWII. The idea was to manufacture a large amount of these pistols, and air drop them into France and other occupied countries for use by irregulars or resistance fighters.
The FP-45 was very secretive during it's design phase. FP-45 stands for Flare Projector Caliber .45. Note that this pistol is not a flare gun. All of the parts were named something innocent - the barrel for instance, was named tube.
A million Liberator pistols were manufactured in 11 weeks. Each of these pistols were test fired at least once. Approximately 600 barrels for the Liberator could be produced per hour. It was said it takes longer to load the weapon, than to manufacture one.
The Liberator was to be air dropped into occupied territories by the British. 500,000 (half) of the Liberator pistols were delivered to Britain before they cancelled the rest. British officials wanted to be in charge of the deployment, but the Americans declined. This project was then pushed aside as the aircraft that would have been used would have been bombers - which had somewhat more important military targets. Furthermore, only a small amount of Liberator packages could be carried per bomber, each bomber needed a larger fuel load to reach the destination for the drop as well as the relatively small bomb bay. Because of these issues, Britain did not air drop a single Liberator into occupied France.
A small amount of Liberators were dropped into Greece, China and the Philippines. Some countries used the Liberator post war in police forces.
After the war, the existing Liberators were either dumped, incinerated, still in service by police forces, or in storage. The OSS acquired the remaining Liberators that were stockpiled in the US.
Liberator (Early Production)
The early production models had an issue where the firing pin block would sometimes rotate slightly, which may cause misfiring.
Liberator (Late Production)
The late production models added a guide rod for the firing pin block.
An unknown company manufactured reproduction Liberator pistols at some point somewhat recently.