It looks like a K-20 camera. (or a previous model of it).
The thing about the K-20 is that you should NEVER dry-fire the shutter as this will kill the membrane that sucks the film flat on exposure.
I would at least cover up the 'pressure plate' openings with a sheet of 4x5" to prevent this from happening, if you're running a thinner film through it.
As for the film transportation having iffy frame spacing, I think that is regulated by the frame-counter taking into account the amount of film wound on the take-up spool.