There is more why DW revolvers are so accurate. To make sure that barrel wouldn't unscrew, manufacturers are making tight fit between frame threaded hole and barrel threaded shank. As a consequence, almost all revolvers suffer from constricted barrel in threaded area. Taylor Throating eliminates noted problem, see
https://www.angelfire.com/ga/alphaprecision/revolveraccuracy.html . Fire lapping is another method to eliminate barrel constriction. DW revolvers do not have such problem because of the sliding fit threads.
Because of the weight I am selling Ruger Redhawk, but keep Bisleys. For the same reason, as soon as I purchase a nice 6" Ruger Security Six, 6" S&W 686 will be for sale