KNS Precision Compact AR/MCX Stock Adapter with Flange

The KNS Precision Compact AR/MCX Stock Adapter delivers all the modularity and versatility of the standard AR/MCX adapter series in a streamlined, low-profile design — without the added rail length that engages the rear AR15 receiver stock plate pocket. This compact adapter allows shooters to mount a Picatinny-style stock or brace attachment — such as the SIG MPX folding stock or SB Tactical FS1913 brace — directly in place of a traditional AR15-style buffer tube.

Ideal for firearms that use the AR15 buffer tube interface for stock or brace mounting but do not mechanically rely on an in-line buffer spring, this adapter provides a clean, modular solution for swapping out accessories without compromising the platform’s functionality or profile.

The two-part kit includes an externally threaded adapter plug that installs into the firearm’s threaded buffer socket or ring, an adapter rail section that seats into the plug, and a hex-socket bolt with lock washer to securely fasten the assembly. The result is a solid, reliable attachment point for a wide range of Picatinny-compatible stocks and braces.

Whether you’re building a custom SBR, upgrading a pistol configuration, or exploring alternative stock solutions for a non-standard platform, the KNS Compact AR/MCX Stock Adapter is a precision-machined, purpose-built solution from a trusted name in the industry.

Order online at Deep Roots Rifle Co for fast shipping nationwide, or stop by our gun store in Eustis, Florida to speak with our knowledgeable staff about fitment and compatibility for your specific build.