If I was going to make the switch, I believe I would go with something other than 223-243. Mainly just because you can, for conversation sake. I'm thinking 6mm AI, 243AI, something not everyone else is shooting... But don't be afraid to leave that 270 just how it is, my brother an I both have Savage 110's in 270 and they both shoot sub 1 inch groups with both factory and handloads.