That 3 each land and groove barrel is the one designed for Minie ball use. Unless they currently cut them deeper, they're .003" deep grooves. It took a long time for figure it out back in teh 60's and is the reason the 1-48" twist got such a bad rap. Another problem was that back then .562" was the closest ball size made by Lyman and others. Just a bad bunch of circumstance. When .570" and .575" molds became available and a good tight ball/patch combo was used, those bores shot balls well. Wasn't twist at all...was tight ball/patch combo that was needed! Voila...magic happened, but people still cuss 1-48" twist because they only heard the beginning of the tale! :wink: :haha: