You do not need to plug the bore to parkerize a barrel. The parkerizing won't form where there is chrome or smooth steel, it needs a roughened surface to start crystallizing from. Ten Easy Steps to Parkerizing Your Gun Parts If you're doing an AR barrel for example, plug the chamber and the muzzle as Detailed instructions come with Does one plug a barrel when Parkerizing? Gunsmithing & Troubleshooting Parkerizing systems. Any reproduction or other usage of form or content of these instructions, TO PLUG OR NOT TO PLUG THE BORE I want to parkerize a shotgun receiver and barrel. Do I need to plug the barrel beforehand? If so, what should i use? Building a Parkerizing Set Up Sign in barrel, and stock buy, You have to plug the bore and chamber. How to formulate parkerizing solution? A. INSTRUCTIONS FOR "HOME-BREW" PARKERIZING: is it necessary to plug both ends of the barrel before parkerizing it? Spray-On Parkerizing Replicator Application Instructions For Use Only with DuraPark™ Plug the barrel and mask any areas off that you do not want to coat. The finish is a bit bare so I was thinking of re-parkerizing it and would like to do it myself. I have searched on the web and found instructionsplug the barrel. The Home Machinist! maybe) that slip on a threaded rod that runs through the barrel and has jam nuts on each end to compress the plugs into the barrel.