A 22" barrel will normally get all the velocity out of a shell, A couple inches to settle the shot, then the choke. There is science involved. A 25" fixed choke skeet barrel is 25" for a reason. A 26" remchoke skeet barrel is 1" longer for more than one reason. The 27 1/2"/28" remchoke barrel is that length, because of the science of the shotgun. Why pack a longer than 22" rifled slug barrel, if no velocity is gained. For practical use All 12ga shotshells preform at their peak in a barrel over 26". My preferance in 3 shot capable guns, 20ga 26", 12ga 28", 10ga 30". I must be fairly normal in my preferances, since these are the most common barrel lengths and they get all the potential a shell has.
