This is one thkng that never made sense to me and seems (at least to me) counterintuitive even though the historical precedents speak for themselves (case in point, the long-barrelled Sherman Firefly variant which became a very effective weapon against WWII German armor that the ordinary Sherman wouldn’t normally be able to penetrate)
The way I see it, the projectile is in the barrel (and therefore engaging the rifling) for that much longer – in that time, more of the shell’s kinetic energy is lost as friction in the barrel than it would be normally, wouldn’t it?
Is the effect of friction negligible and outweighed by the increased rotation imparted by the long barrel? I just don’t understand how it makes as significant a difference as it does.
In: Engineering
The gases from the propellant charge have more time to act on the projectile.
The longer the projectile stays in the barrel, the lower the pressure behind the projectile (because the gases expand) and the higher the pressure in front of the projectile (because the air that was in the barrel gets compressed). At some point, the gain isn’t worth the extra mass of the barrel.
Latest Answers