I discovered the 1:12 twist when I loaded up some of the 240 gr Woodleighs and they keyholed from my Wife's Husky 1600, so I loaded some 180 gr TSXs for her bear load. The 240s stabilize when shot from my ZG-47, but now that I know that I shoot them sparingly.
I have some 220 gr RN Hornadys and some 220 gr Sierra MKs but I don't need to shoot the MKs in the 1:12 to know they won't work; they are significantly longer than the 240 gr Woodleighs. I think the 220 RN Hornadys should be fine in the slow barrel as they are shorter than the 180 gr TSX, but I think the lead core alloy of the newer Hornady bullets is a bit on the hard side for my tastes. I recently recovered some bullets that had the jackets torn away down to the cannelure, but the core had not expanded. That's enough for me to want to test them properly before I load them for any serious work.