they were withdrawn from service in March 1944.
I think that coincides with the tests done with Typhoons and Tempests and the 40mm, doesn't it Jon. But they found the RP just as effective ---
The RP were far less accurate and less effective, however they also didn't require as
close an approach, meaning the attacking aircraft was much less vulnerable to ground
fire, and they were far cheaper, so blasting off a bunch wasn't an issue. Interestingly
the HE round for the S turned out to be more effective than the AP round.