In a rough bore 1893 Marlin .32-40, I tried to duplicate some published very hi velocity loads with very little success. The only hi velocity load that showed any promise was the 170 grain Speer with 35.5 gr of Hodgdon LVR for 2225 fps. 5 shot group at 100 yds, original sights was 3.5". 2100 fps loads with the Speer using RL7 produced a dismal 8" group! If I keep the velocity down around 1500 fps it will shoot any bullet, including cast, with any suitable powder, 4198,RL7,H322,2400 into 2". I guess if I want .30-30 velocities, I ought'a buy a .30-30.
The Marlin requires a very short OAL cartridge, and I have to shave off the exposed lead tip of the Speer .321 170 gr, leaving a flat exposed lead meplat, which accidentally and fortunately seems to enhance expansion at the lower velocities, or so autopsy results on jackrabbits would suggest.
