The New Englander barrel is a round or octagon to round, correct? If so, that may limit the bore diameter it can be enlarged to. Measure the depth of all the screw holes and dovetails. Now double the depth of the deepest holes or dovetail. Subtract that from the outside diameter of the barrel at the muzzle. Subtract .58" (24 ga.) from that number and divide by two. That will be the wall thickness of your barrel. Now, call Bobby and ask him if that barrel will be safe.
Robert Hoyt
700 Fairfield Station Rd.
Fairfield, PA 17320
717-642-6696