Cobalt Blaster Builder

CK-Pro Fast Eddie 13.9″ 5.56×45


  • 13.95” Greenline Tactical/ Rosco Mfg. K9 series hybrid barrel.
    • 5.56X45mm (NATO)
    • 1/7 RH twist
    • Mid-length gas
    • 416R Stainless Steel barrel
    • Electro polished & Nitride coated
    • Continuous taper hybrid contour
    • Recessed target crown
  • Upper: 7075 T6 billet (Features Cobalt S.I.M.S. system).
  • Lower: 7075 T6 billet (feature integrated trigger guard).
  • Handguard: 13” 6061, 7-sided, M-Lok compatible.
  • Muzzle device: RCB-KM
  • Gas block: Cobalt (Non-Adj.), .750 Dia.
  • BCG: Cobalt, Full-Auto.
  • Charging handle: Radian Raptor LT.
  • Safety: Cobalt, Ambi.
  • Mag release: Ambi.
  • Trigger: Geissele 2-stage.
  • Buffer system: A5/ CK buffer system, anti-tilt buffer.
  • Grip: Reptilia CQG-L pistol grip.
  • Stock: Reptilia RECC-E stock (A5 compatible)
  • Warranty: LIFETIME

Product Description

CK-Pro Fast Eddie 13.9″ 5.56×45 Details

A collaboration between Cobalt Kinetics X Greenline Tactical Consulting, The “Fast Eddie” is designed to meet and exceed the criteria for a practical rifle that can perform in the most austere (and unforgiving) environments while still being a refined tool. Critical factors taken into consideration during the design phase were; Accuracy, Operation, Recoil Mitigation, and Ambidextrous Adaptability. The end result is an elegant solution that shows what proper design and meticulous attention to detail can provide. *Final product may differ slightly from image shown. Please reference specs for accuracy of what you will receive when purchased.

Each CK-Pro comes with a LIFETIME WARRANTY.

*Exclusively Available at Firearms Depot

Owners Manual – Download Here

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The Cobalt Difference

Cutting Edge


Cobalt will never be satisfied with the status quo. We are always asking – Why? With our imagination, incredible engineers, and a desire to improve; we are constantly innovating an already amazing platform. We continue to explore how our innovative improvements can make you a faster and more accurate shooter. Innovation is at the core of who we are.

Military Grade


We torture test our rifles and pistols in the most extreme conditions, from the snow to the desert heat, they will function in any environment. The tight tolerances of the firearms protect the internal components from external elements. We Cerakote all our firearms to add to the durability. Multiple sources have reported that they have run our firearms in excess of the 50,000 rounds mark.

Match Grade


Our components are precisely engineered to the tightest tolerances. Our standards far exceed that of other manufacturers. We included match grade barrels and premium triggers in every firearm to enhance accuracy. Our Pro Buffer comes standard to reduce recoil allowing faster follow up shots. From the aggressive look and design to the quality of the components within, we are committed to assembling the finest firearms in the industry.



Every angle we cut, and every component we use, serves a function in our overall design that must be shot to be fully appreciated. At Cobalt Kinetics we source premium parts to compliment our high tolerances and precision engineering. Each component undergoes a strict quality control check before being installed into our firearms.