I have a 45 cal Bill Large bbl and I am getting ready to start a Hawken .The bbl is one Bill made for me 30 plus yrs ago and I,v never used it. I,ll be using a Roller lock and W. Cain trigger and maple wood. All premium parts in my estimation.Time to get started as I,m not getting any younger.We will see if a 1 in 36 twist will work with a round ball.