Air Arms S510 XS Xtra FAC PCP Air Rifle, Regulated, Walnut Stock Precharged pneumatic Sidelever action Fully Regulated 10-shot repeater 2-stage adjustable trigger 5 position power adjustment 11mm scope grooves (no open sights) 3,625 psi fill pressure (250 bar) Built-in manometer (air pressure gauge) 288cc air tank Lothar Walther barrel Shrouded barrel for extra-quiet shooting Checkered pistol grip and forearm Superbly blued Magnificent stock finish Ventilated rubber buttpad Our specs show that this rifle has a 19.75" barrel. The shroud is much longer, and the exterior length from the action to the muzzle measures 24". The barrel is only the rifled portion of the gun.