I have this same issue with my new KW/V6 Black Bay bronze. The action was rough and there was nearly a 1/16" of backplay. I used a razor blade and case knife with scotch tape on its edge to pop the bezel off. It wasn't difficult. I discovered the watch was missing two bezel springs and the spring-loaded bezel click stop was installed facing the wrong direction. I replaced the missing springs by tearing open some old spring-bars and trimming the scavenged springs to size and reinstalled the bezel with the click-stop facing in the correct direction, confident that I had solved the problem. The action was much improved- smoother,firmer, ... but the f**king backplay was still there!
I popped the bezel off again to investigate further and have determined that it is due the loose fit of the click-stop in it's hole. Ideally it should fit like a piston inside a cylinder but the one on my watch wallows around in many microns of slop that translates to the annoying backplay. My few attempts to shim the stop were met with limited success...or what some might call "failure". I ended up just installing a slightly longer spring(scavenged out of a spring-bar)under the stop to increase the pressure against the bezel ratchet. The backplay is still there but you have to use a little force to find it, kind of like a tooth that only hurts when you press on it with your tongue.
