...not one, but TWO FP45s (aka "Liberator" pistols, and no, they aren't mine, but they do belong to a friend of mine, and I've shot both. )
For those who aren't familiar with the FP45, they were developed by the OSS and made by the Guide Lamp Corporation during WWII for the purposes of arming resistance fighters with cheap, disposable guns. The pistol is a single-shot and is made of stamped sheet metal. The idea was to provide a firearm to resistance fighters that would enable them to secure a better weapon (via capture from the now-deceased enemy soldier.) The only machined part is the a smooth-bore .45 caliber barrel and the spring loaded striker/firing pin. It's loaded by pulling the striker/cocking piece back and rotating it 90 degrees. A sheet metal gate is raised, a cartridge inserted into the barrel and the gate is lowered; the cocking piece is then rotated back to vertical and the pistol is fired when the trigger is squeezed. A wooden dowel was included with the gun for use in ejecting the spent cases; spare cartridges were stored in the hollow grip. Both of these are live guns. One, however, was demilled and then reactivated. The other is wholly unmolested.