HiThe whole British anti-tank gun and tank gun saga needs an entire book. Good guns crippled by cheap ammo, bad doctrine and cheap sights. Blame it on the delay getting the 6pdr in to production due to Dunkirk. 6pdr shows up, lather up again and rinse again, cheap ammo, bad doctrine, cheap sights. By now it was 1943.
What are the sources for this? Certainly my father, who used both 2 pdr and 6 pdr guns did not mention these problems, although he did have to walk up the range with a 6 pdr shell that did not fire, the result of a slow burn in the propellant. The 2 pdr sight which telescopic and suitable for low light was considered good and was certainly not cheap!
An anti-tank gun that had severe problems with its ammunition was the US 3in M5, which was "plagued with faulty ammunition from its introduction in late 1942 until early in 1944" according to Ian Hogg on page 88 of 'British & American Artillery of World War Two.
Mike