I wonder if it started out as a 686 that was re-barreled by volquartsen or if it was put together and tuned by volquartsen.
I would suggest you contact volquartsen with everything you know about it and see what they have to say.
Given that nothing jumps out at me while searching google, I don't think a very large number of .357s like this exist. With a name like volquartsen on it, it might be pretty special.
How does she shoot?