150 discarding sabot.

[Marek_Tucan]

Wait, do I get it correct from the report that the 6pdr APDS was just 2pdr shot in sabot? That'd mean it didn't use as much precious metals as tungsten carbide APCR did, thus cheaper and easier to manufacture but with possible worse properties? Was it the same system with 17pdr APDS?

[cbo]

Marek_Tucan said:
Wait, do I get it correct from the report that the 6pdr APDS was just 2pdr shot in sabot? That'd mean it didn't use as much precious metals as tungsten carbide APCR did, thus cheaper and easier to manufacture but with possible worse properties? Was it the same system with 17pdr APDS?

Nope, both had proper tungsten penetrators as far as I know. I'm sure that the report is just repeating the impression that Capt. Rivette had at the time. IIRC normal 2-pdr AP already had issues with fragmentation on impact at normal velocities and would not have been able to achieve the performance figures quoted for 6-pdr APDS.

cbo

[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.