[Dynamo]

that should be about right.

as for your hopup sleeve, i was just about to say something about that, but its good that you figured it out on your own.
i had the same issue with my prowin 8mm mechbox. i stripped 2 pistons befor i figured out that the hop sleeve was out of spec, and not letting the BBs get pushed into the hop by the tappetplate.

and easy test for this - remove the barrel and hold it with the hop sleeve pointing up, place a BB on the oppening to the hopup, then push it through.
the oppening should be just narrow enough to lighty hold the BB from falling though and it should drop in with a light push of a finger.