7mmTCU? It might be a compromise using a 223 case. It will come close to 7-30 Waters performance with less powder and recoil I had one in a 11in Bullberry and it was VERY pleasurable to shoot with 120 NBT’s!
Have you considered a break????
Luv 2 Hunt, the 257 is a great idea, but it has significantly more recoil than that of a 7-30 Waters.