British 75mm MkV tank gun

[CharlesM]

I am Charles Markuss, one of the researchers for the ASL system. M72 AP was solid uncapped shot designed for use against homogeneous armour. By the time it was in service with the British in the M3 the Germans were using face-hardened armour against which the M72 often shattered, like the 40mm 2-ponder AP shot. Theoretically the round was APHE but at the time the USA had no suitable fuze for it. The British therefore simply filled the cavity with inert material to boost AP performance, and did so even after a fuze appeared because the first batches at least were very unreliable. M61 was, as stated, APCBC designed for use against face-hardened armour which was still in use on some parts of German tanks, especially the cats. The US army considered developing an APCR round for their 75mm but the performance increase would have been marginal and really a waste of precious tungsten. If they ever seriously considered it (doubtful) I suspect that the British felt the same way about attempting to develop an APDS round for their 75mm as factories were at full capacity producing 6-pounder and 17-pounder APDS. Moreover, as stated already, I doubt whether the guns would have withstood the chamber pressures of more propellant behind the projectile. APDS is of course also hazardous to friendly personnel. The British and US 75mm guns werre really designed for HE and WP.

Incidentally the US army was given 6-pounder APDS for their 57mm gun by Britain but due to the scarcity of targets only about 180 rounds were ever used in Italy, and something over 11,000 in NW Europe.