I'm shooting one with a 14 twist and JLK 52 gr. LD bullets. These are the highest BC bullet I have been able to find that shoot well in this barrel. I shoot it a lot at 5-600 yards, and took a prairie dog with it at 683 yards two weeks ago. That said, once I get past 400 yards it becomes very wind sensitive. JLK claims a BC of .309. Field shooting, and my ballistics software, say .244 is a much more accurate number. It is, IMO, just not a long range round with the bullets that are suited to this twist rate.
I have debated having it rebarreled with an 8 twist to shoot 77-80 gr VLD bullets, but would strongly consider going back to the .243, or even a 6.5 of some sort as a more suitable long range round.