Most .22lr reaches max velocity between 12.5" and 16-18" or so depending on load and bore condition. Anything over 16" isnt picking up much velocity if any, and MV is much more consistent which equates to greater accuracy especially at longer ranges. As for "what kind fo accuracy can you get" you will have to buy a barrel and find what ammo it likes. .22lr accuracy hinges on barrel quality and ammo consistency. Crap barrels shoot crap groups with any ammo, crap ammo shoots crap groups in any barrel. A good barrel with its favourite ammo shoots good. Dlask makes some nice ones, go for the extreme chamber for best accuracy and stay away from CCI ammo with it. Go sporter chamber for CCI. I havent done any accuracy testing with my 9" NEA as the build was not for accuracy, but it certainly doesnt shoot bad.