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 longer the barrel the longer the explosive gasses get to push on the projectile. The longer the shell is pushed the more energy it has, the faster it will be traveling.
As long as the barrel isn’t so long that the gasses are able to fully expend, then the projectile is going to be getting more energy.
This is why, when the projectile comes out of the end of the barrel, you see the gasses follow it out.
On a pistol, if you have a short 4 inch barrel, the gasses only get to accelerate the bullet for 4 inches. If you have an 8 inch barrel, the gasses get to accelerates the bullet for twice the distance.
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