Originally Posted by indy36
For skeet, 28-inches to 30-inch barrels. For trap and sporting clays 30-inches to 32-inch barrels. For bird hunting in the field, shorter and lighter is usually the rule. So, all things considered, a good 'overall' length is 28-inches.
I have 28" on my Baretta 391 - 12 ga and Remington 1187 20 ga + 870 20 ga.
Why ? Longer barrels just swing smoother. I would also advise you to get a gas gun for skeet w a good recoil pad.
A good instructor can help alot and dramatically shorten your learning curve. (Several good threads on skeet and skeet guns)