I had my Marlin 336 .30-30 with Ballard rifling (1950 vintage) for several years and I've finally gotten around to casting and loading for it. I used the classic 31141 mold, gas checked, sized to .309 and loaded behind 20.0 grains of Reloader 7 as a starter load. First 5 shots at 25 yards grouped in right at 1 inch. (I was using the number 0 as a sighting point). Not a bad start at all.