If I am not mistaken most major shotgun ammo manufacturers test and report their velocity figures after firing from a 30" barrel. If they in fact do this and you are shooting a shorter barrel you will not achieve their published velocity. Read this link from Nitro ammo : http://www.nitrocompany.com/pattern.htm


I' m not going to repost their actual numbers because you can go to the link I provided and read for yourself. I personally use a 28" barrel and it works well for me. It can be a little more cumbersome to move around but I do not mind it.