Chammons, if the gun is not been shot much it may well be it is not broke in. Some one may disagree with this but TC barrels often need break in as far as I am concerned only a few have the polish needed to load smooth to start with.
If you feel it has been well broke in then try a Crush Rid sabot and see if it will group if that work you just have a tight barrel. If its not well broke in you could assist the process by 50 to 100 strokes with a tight patch with a coating of JB bore paste adding a bit about every 3 strokes and changing the patch as needed , be sure to take full length strokes.