Comment by WalterBright
15 hours ago
Airliners are also pretty robust against damage. Although they are not designed to resist explosions, everything is redundant.
This robustness is why fighters in WW2 used cannons for guns. Poking a hole in the side won't do anything.
The USA mostly used .50 caliber machine guns, usually with a mix of ammunition including incendiary bullets so that a hole in a fuel tank meant a large fire. Fighters from the other major combatants usually had 20mm autocannons in addition to smaller machine guns.