Then you can use heavier bullet. Look at Sierra reloading manual. (Sierra Manual shows 1-8 twist) Howa actions: "Measure between the screw holes on the bottom of the rifle. Long is 7 3/8" and short action is 6 1/2". I am thinking you have a long action. J E Custom set out what each action length will do, and the interchange between the cartridge to bolt face. It would be fairly easy to change to a 22/250AI cartridge with heaver bullets with excellence velocity. So you either stay with what you have or change out barrel to a faster twist.Its not done it was just cut with a 1:12 twist from Howa which is very limiting.
The problem is so many twist rates out there.
God bless J E Custom.