The magazine.
This is called the "muzzle" of the gun.
Holster
Projectile, bullet
A powder horn.
It's called a trajectory.
Actually, the proper name is "cartridge." The term bullet is an extremly common but incorrect usage when referring to a cartridge. The term bullet only refers to the piece of lead that comes out of the barrel when the gun is fired. The bullet is one component of the cartridge.
The gun weighs MUCH more than the bullet.
A bullet fired from a gun
Affix the gun to a target. Load the bullet into a cartridge. Load the cartridge into a second gun. Aim carefully, squeeze the trigger. If you have done everything right, you will have shot the gun with a bullet.
It's the recoil from the force of the bullet being fired. The gun powder pushes the bullet forward and also equally pushes the gun back into your hand.
Chastain - Bullet From A Gun
line of flight, or you can also call it a parabolic arc.