I would consider doing a 26" varmint taper and having it heavily fluted. The 1-7 or 1-8 twist as mentioned above should do nicely. I would also consider going to the 243AI if you are handloading. The added brass life alone makes it a viable choice, plus it gives you the chance to get a little more out of it for slinging those heavier bullets way out there. JMHO's of course.