SKU: KEA1-50-01-708
The KE Arms M4 Stock Assembly 9mm 5.5oz is a complete rear-end kit engineered for operators building or upgrading AR platform rifles. This all-in-one assembly delivers the precision and reliability demanded by law enforcement, military, and serious civilian shooters who require a proven buffer system optimized for 9mm subsonic and standard velocity ammunition. Every component is manufactured in the USA, reflecting KE Arms' commitment to domestic quality and traceability.
The kit includes a billet mil-spec buffer tube, KE Arms' purpose-built 9mm 5.5oz buffer, matched buffer spring, mil-spec endplate, billet castle nut, and standard buttstock. The 5.5oz buffer weight is specifically tuned for 9mm bolt carrier assemblies, ensuring proper dwell time and reducing carrier tilt that can cause premature wear on internal components. The billet construction of both the tube and castle nut provides superior durability compared to forged alternatives, with tighter tolerances that minimize wobble at the rear of the receiver extension. This level of precision matters on duty rifles where reliability cannot be compromised.
This assembly is ideal for 9mm AR builds, 80% lower completion projects, or retrofit upgrades to existing AR platforms. Whether you're configuring a patrol carbine, training rifle, or cost-effective 9mm defensive system, this kit eliminates guesswork by bundling all necessary rear-end components in one purchase. Operators appreciate kits like this for range sessions, qualification cycles, and duty applications where quick assembly and verified component compatibility are non-negotiable.
The 9mm AR platform has become standard across training facilities and duty arsenals due to low recoil, ammunition cost, and shooter control advantages. A correctly matched buffer system is essential to maximize these benefits. KE Arms stocks are available in multiple weight configurations; the 5.5oz version is the specification for 9mm, distinguishing this kit from standard 5.56mm assemblies that would cause reliability issues in a 9mm platform.
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