The rewording opens things up for a few more cartridge options (the old wording had a specific list of permitted cartridges), but it still makes little sense. The fact that one can use a .45-70 but not a .30-30 makes no sense when the underlying premise for the restrictions is a concern for safety due to the potential distance the bullet could travel on a miss. As Mike points out, the wording is very vague and raises the question as to whether belted magnums (.450 Marlin, .458 Winchester, etc) would be legal.
The old law was far more capricious. It was a laundry list of specific chamberings, and it looked like somebody had gone to the closet and cherry picked their favorites. By my read of it, 450 Marlin and 458 Magnum are in.
These rules only make sense when you figure in the underlying conflicts. On the one hand you have folks that don't want deer hunting at all allied with bowhunters. Farmers are split. Some see anything that reduces the deer herd is good. Others don't want high-powered rifle bullets coming through their walls. I've been following this fight since I started hunting Ohio in the early 80's. This is one of a series of baby steps the ODNR has taken over the years to move to allow all centerfire rifle, but they've had to manoeuvre a lot through each step.
When I got started it was just an accepted catechism that Ohio was too densely populated for anything but shotguns, and if it was not that way, there'd be a massacre. Even today, there is a major contingent of deer hunters who think this way, or else think Ohio hunters are somehow superior because they hunt with shotguns.
