150 discarding sabot.

[CharlesM]

Agreed, but 2 pdr shatter problems were due to uncapped AP shot being used at German face-hardened armour in N Africa; the US 75mm M72 AP round had similar problems and later both the 2-pdr and US 75mm got APCBC rounds that cured this problem. At the 3900 or so fps a plain steel (i.e. non-tungsten) APDS core would shatter on impact. I have never been able to confirm that the 57mm APDS core was exactly 40mm, but it would seem logical.