Walker, interesting question. I don't think they even called it "Ballard" rifling in 1972. The rifles in question also had Douglas barrels. The "B0" designation is only found on Marlin 1895 rifles manufactured in 1972.
I don't think they used Ballard rifling, either. Mine is micro-groove.
The Ballard rifling I think is a fairly recent thing for cowboy shooters and lead bullet shooters who want to get some speed behind a heavy lead bullet.
I LOVE my 1895, but seldom shoot it. Nice-looking, no pistol grip and no damned safety.
