Airsoft Tight Bore Inner Barrels 101 Generally, the longer your inner barrel is, the higher your accuracy and range. Generally, you want your inner barrel to be as long as your outer barrel without being exposed. The tighter bore the better air seal. At the cost of easier Jam if you are playing at dusty ares. It is highly recommended that you only use Evike, Matrix, Angel Custom, WE and compatible high precision bbs for your Airsoft gaming.