era un cañón de baja presión, eso significa menos velocidad de salida.
Originally, it had been expected that the tank would use a new gun from Vickers: the "High Velocity 75mm". However, as designed, the gun would not fit into the turret size available. So the gun was changed to a different gun, the "77mm HV". This gun used the same calibre (76.2 mm) projectile as the 17-pounder but the shell casing was from the older QF 3 inch 20 cwt anti-aircraft gun loaded to higher pressures. The resulting round was completely different from 17-pounder ammunition. It had a lower muzzle velocity than the 17-pounder but the ammunition was much more compact and more easily stored and handled within the tank.
la munición del 17 libras normal ya era de alta velocidad, el cañón lo que era era más cómodo de uso
el cartucho del "nuevo"17 PDR era significativamente más pequeño, así que tenía menos carga de proyección http://en.wikipedia.org/wiki/Ordnance_Q ... r#77_mm_HV