Star B/BS were all built for 38 Super and the mags were appropriate for longer cartridges. 9mm were a short fit but worked except were inclined to nose dive. SA Defence Force standard handgun in 9 mm since the middle sixties, still in use.

If the gun had a 38 chamber and you used 9mm, the extractor kept it in contact with the breech face, otherwise it would just have slipped into the chamber.