Lurch,
I understand not wanting to waste money if not needed. Fix the plug, BUT before you re-inlet it, buy a couple of books, figure out a plan of attack. Thing MUST inlet in the proper order when building a gun.
Pull the breechplug, and inlet the barrel completely, with full contact on the rear of the barrel, then reinstall your plug, and inlet it, with full contact on the rear of the barrel again, and with the rear of the recoil lug.
Sharp tools are a MUST. There is no such thing as too sharp.
Recreating the American Longrifle, and The Art of Building the Penns. Longrifle, are a MUST HAVE, before you get too far down the road.
My Friend, if you continue on the path you're on, without some direction, you are gonna HATE the building process.
Good luck.