Airplanes were still relatively new when they were pressed into service during World War I. Because of this, a number of hurdles had to be overcome to ensure that this new machine could become a weapon of war and not a casualty of war. The biggest hurdle became obvious right away . . .
without an interrupter gear, the machine guns will cut through the propellers and the plane will crash. Another hurdle: hot brass.
Any shooter who’s spent some time on the range knows that hot brass can be quite uncomfortable and disruptive. The last thing anyone needed during an aerial dogfight was for the pilot to become distracted by a piece of hot brass landing somewhere it shouldn’t.
Errant brass could also prove to be detrimental to the plane’s equipment itself. If a piece (or pieces) got caught in the mechanical workings of the plane, it could have a catastrophic result.
Enter cartridge catchers.
These devices fit onto the frame of a pistol, situated to the right and rear of the ejection port. This enabled the brass to be ejected as normal and caught safely in the metal trap. The shooter could now engage the enemy — yes, while flying the aircraft — without worrying about burning himself or his co-pilot, or possibly jamming any of the plane’s operational parts.
These days Air Force pilots carry the standard 9mm Beretta with extra magazines. No cartridge catchers need apply.