Typically if you buy a good quality gun with fix sights they will be very accurate strait out of the box. Given your only interested in short range, trying to fine tune your adjustable sights may not be worth it, I'd probably go with the extra 1/2 inch of barrel. Remember a longer barrel not only improves accuracy in most cases, but also helps to reduce muzzle flip thus allowing you to re-acquire the target faster which can be of great help in compitetions.
