The shot with a firearm gives at the same a violent backward movement which, in the case of long gun resting on the shoulder of the shooter, submit him to a violent blow, surely annoying but that can also be harmful if it isn’t within certain limits . But what happens in reality?
The explosion of gunpowder tends to separate the projectile from the weapon; in other words, it latter pushes the shot on the one hand and the gun in the opposite direction.
Speaking of a purely physical phenomenon is also possible to say that both elements will move in the their direction for an area that is inversely proportional to their mass. So ironically, if the rifle had not stopped, in his retrograde movement, from the shoulder of the shooter it would have a movement of 100 times less than that of the projectile (evaluation performed on a standard data, which provides that the gun weights 100 times more than the charge that launches. Example: rifle weight 3,200 gr and weight launched shot 32 gr).
The recoil shotgun
The sensation that produces the recoil on the shooter is obviously a function of the amount of kinetic energy produced in the explosion but also of the weight of the shotgun. It’s a well-known fact that firing the same ammunition by two shotguns different for weight the recoil felt is different and clearly lower for the gun that weights less.
The living force of the recoil is influenced by many factors: the weight of the shotgun, the weight of the shot charge (or projectile) including the material of wad and the burning rate of the powder. It is, however, independent of the value of the maximum pressure.
Shooters with a medium build resent a recoil of 4 kgm, factor that will make them lose their concentration worsening the quality of the shot.
Recoils with power about 4.5 kgm can be supported well by important build shooters as long as they engage hunts where they shoot rarely.
During hunts where the hunters tend to shoot with good frequency, such as those in bars, in the English hunts or to the small migratory, the recoil becomes an important factor that can affect the hunting results.
The speed of the recoil, a direct function of the burning rate of the gunpowder, is measured with a special instrument called “velocimeter”; in this the gun is placed on a horizontal axis capable of measuring, on a graduated rod, the weapon retrograde displacement during the shot. This instrument was used in the past, particularly in British plants for the production of ammunition.