Bartlein Cut-Rifled Barrels are known for exceptional uniformity and finish of the bore. The Bartlein rifling machines are so accurate, the company can carry the twist rate to the 4th decimal point (example: 11.3642). The process of Single Point Cut Rifling is the most stress free way to rifle a barrel. The twist is exact, where as other forms of rifling can have variances due to the process they use. In addition the bore and groove dimensions are more uniform.
Bartlein Barrels are pre-lapped before rifling and finish lapped the barrel after rifling. There is no need or under any circumstances, should you fire lap or do any other sort of bore polishing to the barrel. A lapped barrel will not wear out earlier vs. an unlapped one. Bartlein barrels will typically last longer than a button barrel, or similar.