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. This makes the guns deadly accurate.
The rail barrel is manufactured from aircraft grade aluminum. The mechanism is manufactured from glass reinforced nylon and also has a solid 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.