Surprised no talk of 375 Win? I've had two Marlin rifles chambered in this, one factory, one JES rebore, and my reloads were pushing a 200gr .375 JFN slug at 2400 fps, zero pressure signs, 220gr bullets were not much slower. Talk about a deer thumper. Plus you just use starline 38/55 brass, the short stuff. This thing was a HAMMER and easy to load for with factory brass and a straight wall cartridge that loaded like a pistol round. JES does a lot of these, it's just a 30-30 case blown out straight (as I remember). But it's also an entirely different power level from a 30-30. Might be too much.
Also worth noting that my boring 336A with it's 24" barrel gives 2390 fps with most factory 150gr loads...It's way faster than a 20", though goofy looking.
