Teacherjh wrote:

If the bullet hits the s in at a shallow angle, there will be much less force
perpendicular to the skin, and it will be less likely to be punctured. The
bullet will just ricochet.

I think you've confused the skin of an aircraft with that of an armoured personel
carrier. It won't ricochet off a car, much less a plane. Still, the usual pistol
round is unlikely to do much damage unless it hits a structural frame just right
or hits equipment (such as an engine) outside the cabin.

George Patterson
Great discoveries are not announced with "Eureka!". What's usually said is
"Hummmmm... That's interesting...."