From a shorter 22" barrel, I'd go 308, 7mm-08 or even 30-06 as these will give closer to advertised velocities. Actually, 7mm-08 would be perfect. Its nipping at the .270's heels already WRT energy and flatness and if your .270's velocity is cut a hot 7mm-08 load might even edge it out in both catagories and have more bullet options for the reloader and more efficient powder usage. And, the 7mm-08 has 15-25% less recoil than a .270. Personally, I wouldn't buy a .270 or a .25-06 without a 24" barrel.