Picked up a used automag classic and looking for suggestions. It is sputtering only when I release the trigger. Sputter stops relatively quickly and can fire again. When I tried the valve out in my ule mag it seems good. Sear seems to have the proper gap to trigger.

Sear doesn't seem to have much wear but can that be the problem?? Any suggestions? A bit rusty so I don't know where to start

Thanks