Mark, you might want to ask this question on the "Modern Inline Muzzleloading Rifles" forum. A lot of guys are having custom work done to their factory barrels which entails cutting off the OLA and recrowning the barrel. That QLA on the end of the ML barrels can make it hard to get good consistent groups. Looks as though it's just a marketing gimmick and the TC's might be more accurate without it.