In 1936, Lewis Nolan Nomar patented this device, which is basically a large 40-round magazine for the 1911 pistol. He envisioned a military use for the device in trench raiding, giving men a compact weapon with a large capacity. Unfortunately for him, the device was both remarkably (and unnecessarily) heavy and obsolete the day it was patented. Not only was trench warfare a thing of the past, but submachine guns could and would do the job of his device better than it could. Ultimately, I believe only two of these were made and was never formally tested by the US military. Nomar may have also experimented with adapting it to other handguns beyond the 1911, although I cannot find any firm evidence either way on that point.
Union Pistol w/ Horseshoe Magazine: https://www.full30.com/video/a21c708a3d2c5a45396412810da3091a
Slow Motion Artillery Luger w/ Drum: https://www.full30.com/video/f8536c16cb1d2615acdb6fce78835ad5
Benke-Thiemann Folding Luger Stock: https://www.full30.com/video/2686a2e16a85dc9309b9b444702a674b