22/243 with 14 Twist
I had a24 inch 14 nTwist 22 ppc with a few rounds on it, still in great shape. I re chambered the 22 PPC to a 22/243 AI using a reamer with zero freebore. Now shooting the 60g Sierra HP at 4000 fps into a bug hole.
Carbon fouling is a serious issue with this cartridge, and I hope you have a bore scope to monitor the fouling.