Mike, longer barrels help one follow through on deliberate, swinging shots, e.g. ducks or doves. For quicker, usually going-away "snap" shots, as are more common on ruffed grouse and quail, shorter barrels can allow a quicker poke, due to less inertia to get them moving (rocketman?). I've found 28" to be a good compromise, although I have doubles with 26" to 30" barrels. Target guns are a different story, which someone else will have to address since I don't shoot clays anymore (exacerbates my flinch too much). I've also found that I prefer my light (5-6lb) 28ga guns to have a little bit heavier/longer barrels and my heavier (7-8lb) 12 ga guns to have a bit lighter barrels, moving the balance somewhat rearward. It's mostly up to personal preference.
Joe
