I used to have a S&W 4" 686 that Andy Cannon made in to a "Street L".
It was the design genius of Massad Ayoob and Andy Cannon. Basically it was a "slicked up" 681/686 with a Patridge Front Sight, DAO, "Bobbed Hammer", Relieved Trigger Guard (mine was relieved on the left side because I shot left handed), "New Style" Cylinder Release Latch (This was before they were common), the Square Butts were converted to Round Butt, and the "piece de resistance".
The "piece de resistance" was the Compensator milled out of the end of the barrel. What Andy Cannon did was move the Front Sight back, making it a 3" gun, and put his compensator at the top of the end of the barrel. It was a HUGE gaping Comp that really reduced recoil.
I really miss my "Street L" and I'm tossing around the idea of having something similar done locally by a couple of different gunsmiths. I will have to use at least two, maybe three shops to get what I want because each shop has their "specialty" where as Andy Cannon had all the "specialties" in his shop. He was a great gunsmith and I'm sorry I lost my "Street L" years ago.
It was designed as the "Ultimate Fighting Revolver" for a street cop. It's demise was that it came out when the 9mm craze was also coming out.
Biker