science, Bullet markings and check them with the rifling of the firearm. Barrel twist and or markings can help ID the gun fired from. Nothing can tell you for sure, It can just tell you it was fired from a barrel like that of a type or make.
The only way to be certain is to remove the bullet with a bullet puller, empty out the powder, and weigh it.
bullet proof shotgun bullet proof shotgun
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.
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
A bullet leaves a gun barrel because it is forced out by the pressure of burning gasses.
The bullet is moving forward, and is spinning. As the bullet moves away from the gun, it falls towards the earth from gravity.
bullet+metal=gun
bullet+metal=gun
That is where the bullet comes out of the gun.