Fully rigged and ready to shoot! Rob Allen aluminum railguns have the same dimension as the carbon barrels. The extended "rail" incorporated into the aluminum barrel supports the spear the full length of the barrel on into the muzzle. The Rail level lines up with the profile of the mechanism and the muzzle. The integral rail is part of the barrel, thus increasing stiffness and reducing flex. This makes the guns deadly accurate. The rail barrel is manufactured from aircraft grade aluminum with a wall thickness of 1.45mm. The mechanism is manufactured from glass reinforced nylon and also has a solid 316 stainless steel sear. The Rob Allen Tun Railgun comes with either the Rob Allen Low Profile Open or Closed muzzle which is smaller in profile than conventional muzzles providing less drag and greater maneuverability. Rob Allen Vecta Aluminum Railguns are available in lengths from 70 cm to 140 cm.