Can anyone please confirm what the actual (measured) velocity is from the 604 (pellet dependant of course).

Also whether there is any difference in velocity between the Mk1 and the Mk2. I understand the Mk2 was slightly longer so maybe that affected the length of the barrel/air cylinder.

I have read one bbs thread that mentioned that the 604 fell short of the published 400fps, and read on other forums values of 370fps even when seals have been replaced.

Thank You