Able to seal itself when punctured, a gasoline tank intended for war airplanes automatically stops gasoline leaks through bullet holes. In a recent test the self-sealing tank, filled with Barks-Toiis gallons of gasoline, remained tight and lost very little gas after being penetrated thirty-two times by thirty-caliber armor-piercing bullets fired into the tank, although gaping holes were riddled in its. aluminum alloy shielding.