In a 14" barrel my 6.5 GR (sharp shouldered thutty thutty necked down) would push a 120 gr 2400 fps. I'd guestimate at 22" tube should get that 120 going 2700 fps. Unfortunately the 30-30 case is thin and prone to case head sepperation.
Assuming this is a project for a single shot and hence the use of a rimmed case, I'd propose and interesting mild mannered 6.5 that would shoot tiny groups and have mild recoil. A 6.5br rimmed. Take .444 brass, trim to 1.5" and neck it down. Sure, a little bit of work, but odds are you'd have the only one around, and it should be wicked accurate. Looks like 120's at about 2800 fps, and 140's at 2500 fps.
