As to recommended gunsmiths, I think Buck Hamlin is fairly close to you.

Buck Hamlin (636-479-4304)

Daryl is right that you might be referring to aftermarket ported barrels, not a "de-wat". My mind went to a BHE Parker I saw about 50 years ago which went out the back door of a police department - barrels cut to about 12", and someone drilled about 1/2" holes into the chambers.