I have an original southern mountain rifle that uses a repurposed early hand forged swamped barrel. I believe the barrel to be a good 60 to 80 years older than the half stock it is currently setting in. If you want to use a swamped barrel to make a half stock, it's your rifle, do as you please. Now, with that said, my rifle does not have a under rib. using an under rib on a swamped barrel will present some challenges,but it could be done.