This Mil-Sim 14" rifled and gun-drilled barrel is specifically designed for woods and scenario paintball. However it can be used for speedball. The barrel breech is "Permanently Threaded". The marker has a "Fixed" counter-bored and ported muzzle that is designed to collapse the pressure wave in front of the ball. Because these barrels are threaded directly to the marker without a sizer, we recommend you select paint that matches the bore using 0.688 paint for best marker efficiency and accuracy results.