Conical twist barrel are not just the twist but the depth of the rifling and how it is cut. For instance I have a couple Knight Rifles that while excellent sabot shooters, are not that great in the conical department. Yet I have three Whites and all of them are conical throwing marvels.

Now I am no barrel maker, but something makes the White what it is and something makes other barrels what they are. Also do away with any QLA. I think they are a waste of effort. Now a inward side into the crown of the muzzle is one thing. But a false muzzle I feel just is not needed.