Got a physics question

[Royal Tiger]

As for the round out of a gun, when the first jets were entering service, they realized they were flying into their own gunfire, so machine guns were phased out for higher velocity cannons. The .50 cal is long gone from fighter aircraft, replaced with 20mm cannons.

[Electrophil]

That and the lack of gravity causing a downward force to go along with the horizontal force to make the circle.