RIFLE: REX TACTICAL ARMORY MODEL RX-15, SERIAL NUMBER R15-00206, OTHER, NO CASE INCLUDED, SEMI - AUTOMATIC, .300 BLACKOUT, 18 Notes: Rifle: Rex Tactical Armory Model RX-15 Rex Tactical Armory RX-15 Serial Number: R15-00206 Barrel Length: 18" Caliber: .300 Blackout Action: Semi-Automatic Case: Not Included Quantity: 1 Rex Tactical Armory, Model RX-15, serial number R15-00206. The firearm is identified as having an "Other" finish or Tan/Grey, an 18-inch barrel, .300 Blackout chambering, and semi-automatic action. The item is recorded as a rifle and is not accompanied by a case.