PLUS ONE to MAJOR 2 !!!!
The fastest method I know to completely ruin a Shotgun is to attack it with a Brake Cylinder Hone. If you absolutely MUST mess with your chambers, the Chamber Hone and Honing Oil from Brownells is the ONLY way to go. For a light polish, a brass brush wrapped in 0000 steel wool and a dab of oil will suffice.
Most of the problem with Double guns spitting out fired hulls is the choice of hulls. Feeding an expensive or well set up Shotgun with cheap ammunition is Oxymoron. You may well have to go through many different hull configurations to get the one your gun likes.
I'm somewhat Opinionated (No ... Really ..... It's TRUE). I don't care at all for Single Trigger double guns. I use, like, recommend and strongly suggest Double Triggers. With double triggers, you essentially have TWO separate Shotguns, joined at the hip. Way more reliable. A Stoeger, lightly managed will serve very indeed. You can spend gobs more. However:
Your not going to shave 20 - 30 seconds off your stage times with a change of Shotguns. No way, No How. Not gonna happen. The only thing that will shave 20 - 30 seconds of your stage times is practice. By your definition "Gucci" Shotguns, regardless of manufacturer are not top level competition ready "out of the box." When you speak of 20 - 30 seconds, the kind of practice your actually looking at is somewhere around three to seven THOUSAND rounds a week. Working with ALL your guns and perfecting your transitions. Excellence is an acquired flavor. A simple change of hardware ain't gonna get you there.
Coffinmaker