MPN: M109UB0B / 2M109UB0B
*This upper receiver assembly has a barrel that is shorter than 16". This upper is only for use on AR pistol lower receivers and NFA registered Short-Barreled Rifle (SBR) lower receivers. All NFA laws apply!
In the PWS MK109 300 Blackout Upper, Primary Weapons Systems offers a high-quality long stroke piston system with an 9.75-inch 416R stainless steel barrel chambered in 300BLK. This is a compact 300 Blackout upper that still functions well under suppression and has been field proven by a number of operators in real-world situations, even at distances as far as 300 meters. The MK109 is a variation of the Primary Weapons System MK1 long piston upper system.
In designing the MK1 Upper, Primary Weapons System sought to bring the nearly infallible reliability of the AK-47 and the agility and adaptability of the AR platform together to create an advanced upper that is more reliable than direct impingement gas operated uppers and more ergonomically forgiving than the stolid AK. The result is an upper that operates well with less total pressure than direct impingement systems, has fewer moving parts and requires personal maintenance to keep it in excellent working order. The MK1 has a better service life and fewer issues with fouling than its predecessors, freeing the operator actually complete his mission rather than pampering a finicky firearm.
In the PWS MK1, Mod 1 certain vestiges of the previous generation held on. If you prefer a more Mil-Spec design upper and you’re hooked on the promise of the forward assist, the Mod 1 is for you. If you’re ready to let go and step further into the future where the competition doesn’t dare go, take hold of the next evolutionary rung and try a PWS MK1 Mod 2. The PWS MK1 Mod 2 300 Blackout upper features a surface machined forged receiver without a forward assist. The resulting loss of mass easily approaches the standard set by machined billet receivers but does so with the superior strength and service life of forged units. Both evolutions of the PWS MK109 Blackout use a gas block to help manage pressure, but unlike uppers chambered to .223, the block is not adjustable.
Because It’s Time… You know you want the reliability of the revolutionary PWS 300 Blackout piston upper, simply choose the model you’re most comfortable with and evolve.
NOTE: For the protection of our customers and various safety and legal liability reasons, we do not accept returns on ammunition, firearms, barrels, or any product that contains a barrel. Defective firearms, barrels, any product that contains a barrel (i.e., complete AR-15 uppers, complete pistol slides, etc.) and ammunition must be returned to the original manufacturer for warranty service. You can have peace of mind that all firearms, barrels, complete uppers, and ammunition that we sell are brand new from the manufacturer, and have never been used, installed, or modified.