Rigid R175RNF Won't Advance Nail Coil

So, I bought a used Rigid R175RNF coil roofing nailer off eBay and it drove the first nail fine, but then would not advance the coil of nails to put a new nail into the firing line. Turned out to be a worn O-ring in the piston that moves the sliding device that grabs the next nail and advances the coil. The pneumatic pressure pushes the piston aft, then spring pressure pushes the new nail into firing position. If you're having the same problem, this video will show you how to replace the O-ring that is the culprit. Thanks for looking.