My thought is that the chambers may have been undersized on purpose. If you think about it, this gives the buyer of the revolver the option to size the chambers to their needs, while retaining the tight freebore in the cylinder ahead of the chamber. If the factory's logic was that these were designed as competition guns, where some gunsmith work would be done as a matter of course, then that assumption makes sense. Anyways as I wrote earlier the post-reaming "dual size" of the cylinder I believe will give the best of both worlds, accuracy and function. Of course in a perfect world, reaming the chamber to SAAMI sporting spec, rather than dealing with bolt-gun territory SAAMI match chambers in a hand-ejected revolver, would not be necessary, and the factory would have found a way to use the extra length of the cylinder in front of the chamber as an accuracy aid without impinging on function.