I'm building one. Got a 50 cal liner and turned it to fit a 16 ga shot gun. Cut a couple dove tails for some vintage looking sights. Added a fore arm from a H&R muzzle loader, filled the ram rod channel added a barrel band spring to hold the barrel ban in place. I changed the butt plate to a vintage looking steel one. I have yet to cut the chamber and add a saddle ring. It looks like a carbine circa 1880 or so. Progress is slow due to life's little hurdles. Hope to shoot it this sping.
going to use BP.