Some mangled cases last range trip...

[cwlongshot]

OK,
Took both frames side by side and compared things...  The G20 frame has a short 1/4" long ejector, while the G21 has a bent much longer ejector over 1/2" long.

With the slide locked back, the G20's ejector stands 1/8"exposed while the G21 stands with nearly its full 1/2" length showing.
IMHO the G21 frame is causing the longer 10MM case to slam HARD on the side of the chamber then slide as it ejects. the added length is needed for the shorter 45 ACP case.

CW