I built a smaller rifle, still have it. I salvaged a .38cal barrel someone had messed up the breech on. Shortened it, but I should have gone even more since kids still have trouble shooting it offhand. Used a pistol flintlock on it, stock out of cherry since it's lighter then most wood, cut down a buttplate to fit propotion wise. Easy enough to do. Yes, at one time .38's were out there, you just need a mold to match.