Simple barrel swap, I'd look seriously at the 6X45. 6-204 Ruger or 6X47 Rem (6mm-222 Rem Mag) would also be a good choice. I have the 6X47 and get 3100 fps out of 70 grain Nosler BT with a 20" barrel, and am waiting on a 22" 6X45 barrel from X-Caliber with a 1:7 twist.

I've been thinking the new .22 Nosler necked up to 6mm, .257, or 6.5mm might be fun to play with as well. That'll require some magazine tweaking as well as the barrel swap. However, before I go wildcating the cartridge I'll wait and see what Nosler does.