Hawken barrels are octagonal; New Englander barrels are round. They do not interchange.
Depending on how bad it is the pitting may be correctable by scouring the bore with rust remover. Get a cleaning jag for a smaller caliber, wrap it with 0000 steel wool and saturate with a good rust remover - naval jelly, kroil, liquid wrench, etc. Scour the bore with several strokes, then coat the bore with the rust remover and let it sit overnight. Repeat the next day, checking frequently for progress.
This won't correct bad pitting but it will clean up the lesser amounts. Minor pitting is not a great concern, but moderate pitting ruins the accuracy of the barrel and can even render it unsafe if it's extreme.
A phone call to Thompson Center's customer support might be in order; they may have spare New Englander barrels.
Depending on how bad it is the pitting may be correctable by scouring the bore with rust remover. Get a cleaning jag for a smaller caliber, wrap it with 0000 steel wool and saturate with a good rust remover - naval jelly, kroil, liquid wrench, etc. Scour the bore with several strokes, then coat the bore with the rust remover and let it sit overnight. Repeat the next day, checking frequently for progress.
This won't correct bad pitting but it will clean up the lesser amounts. Minor pitting is not a great concern, but moderate pitting ruins the accuracy of the barrel and can even render it unsafe if it's extreme.
A phone call to Thompson Center's customer support might be in order; they may have spare New Englander barrels.