I had a Harrington and Richardson single shot that was in 410 3in & 45LC with screw in choke , rifled barrel , not very accurate with the 45 LC , it had small firing pin & the rifle action rated to 270 , 30/06 so I tried 454 Casull , did a proof test fire how ever , no problem & was more accurate , then I got 30R Blaser cases blow them out and loaded with heavy 45LC slugs , good accuracy as no free bore & more power than a 45/70 !

The 444 Marlin were not the answer in my gun , but 9.3X74 blown out & shortened were close as I remember ?