Holster
This is called the "muzzle" of the gun.
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.
The total momentum of the bullet and the gun before firing is zero, as the gun and the bullet are at rest. Momentum is the product of mass and velocity, and since both the gun and the bullet are not moving, their momentum is zero.
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.
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.
Chastain - Bullet From A Gun
Yes, forensics experts can use a process called ballistics analysis to match a fired bullet to the gun that fired it. This involves examining unique markings left on the bullet by the barrel of the gun, such as striations or rifling marks. By comparing these markings with test-fired bullets from a suspected gun, investigators can determine if there is a match.