I lucked into 16 # of WST so use it for several guns. If you have used WST in a Marlin Cowboy what is the largest charge used. I am using a Little Dandy #13 rotor for my 250gr .45 Colt Loads but wonder just what the max load would be in the rifle. Grandson used my load to take a nice doe this year. Setting with to much time on my hands. Sorry