I think the 257 by physics calculation with the normal bullets specified by ULA24 would have the least recoil. None of them recoil very much though. For muzzle blast, I'll bet there all the same with same length barrels.

What are you looking at hunting/shooting? A 7mmTCU (IIRC a 223 necked up to 7mm) with 120gr bullets sounds like what you're looking for. No recoil, minimal muzzle blast.

RH