Ammunition
The 17-pounder used two types of anti-tank ammunition. APCBC (Armour Piercing, Capped, Ballistic Capped) ammunition could penetrate 140 mm of armour at 457 metres and 131 mm at 914 m at a 30 degree angle. APDS (Armour Piercing, Discarding Sabot) could penetrate 208 mm of armour at 457 m and 192 mm at 914 m at a 30 degree angle, allowing it to penetrate the armour of even the redoubtable King Tiger tank. However, APDS was much less accurate than APCBC ammunition, and did not do nearly as much damage to an enemy tank if it did penetrate. APCBC ammunition was standard; APDS shot was used for about 6% of the average loadout of a 17-pdr equipped British tank.
The HE shell initially developed for the 17-pdr lacked power: due to the high-powered cartridge; the shell walls had to be thicker to stand the stresses of firing, leaving less room for explosive. Reducing the size of the propelling charge for the HE shell allowed the use of a thinner-walled and more powerful shell.
The 17-pdr produced a very large muzzle flash due to the large amount of propellant in its cartridges. Muzzle blast was also significant, described by crews of the anti-tank gun variant as resembling a hard slap on the chest.
Read more about this topic: Ordnance QF 17 Pounder