[VooDooPeteK]

OK so here is the deal

I took apart one of my MP5's to add/fix the following

nozzle, tappet plate, spring and piston head O ring

After I put everything back together it would turn over then jam up with the piston locked back.

I took it apart again (and again, and again), reshimmed it but it continues to do the same thing. Even tried putting the old spring back in thinking that might be in.

At this point I am at a bit of a loss as to what it might be so I am turning to the experts here for advice on what I should be looking at to solve this issue.

Thanks