I recently saw a documentary on TV where they said the Germans produced higher velocity from their AT guns by tapering the bore at the muzzle. It seems to me that this should slow down the projectile. Does anyone know how this worked.
See 'The Armour Problem' section of this article: http://www.quarry.nildram.co.uk/highvel.htm The taper bore did not increase the velocity compared with firing the same ammo in a straight-bored gun (i.e. with the same calibre as the projectile before it was squeezed); in fact, the friction of squeezing it down to a smaller calibre almost certainly reduced the muzzle velocity. The high velocity came from the fact that the cartridge fired a lightweight projectile with a lot of propellant behind it. The purpose of squeezing it down was to reduce the air drag and hence the velocity loss with distance. Tony Williams: Military gun and ammunition website and discussion forum
