I have fast twist barrels in both the Thompson Center and the Green Mountain Barrels. I have no idea of the depth of their rifling cut. I do know that both of them are great shooters. I am more them pleased with the way the new Stainless Steel Green Mountain Barrel I put on one of my Renegades shoots. It is accurate and tuned in real fast. My Thompson Center inline rifles shoot excellent as well. I'd hate to live on the difference between them.