The KNS Precision AR/MCX Stock Adapter (brand part no. AR-MCX Adapter w-o Flange) lets a shooter mount a picatinny-style stock attachment, such as a SIG MPX-pattern folding stock, in place of a standard AR-15 buffer tube. KNS Precision built this adapter for firearms that use the AR-15’s buffer tube attachment to mount stocks and braces but do not mechanically require the tube for an in-line buffer spring. The kit is composed of two parts and an attaching bolt: an externally-threaded adapter plug that fits the threaded buffer socket, and an adapter rail section that locks into the plug and is secured with a hex-socket bolt and lock washer. It is intended only for applications where the bolt carrier and buffer tube do not protrude past the receiver ring, and it will not work on a standard AR-15 lower paired with an MCX upper.

Key Specifications

• Provides a modular mounting point for a picatinny-style folding stock or brace in place of a standard buffer tube.
• The kit includes an adapter plug, adapter rail section, and attaching hardware as a complete two-part assembly.
• The adapter plug is externally threaded to fit into a threaded buffer socket or ring.
• Secured with a hex-socket bolt and lock washer for a solid, non-shifting attachment.
• Intended for applications where the bolt carrier and buffer tube do not protrude past the receiver ring.

Frequently Asked Questions

What does this adapter let me do? It lets you mount a picatinny-style folding stock or brace in place of a standard AR-15 buffer tube.

What is included? An externally-threaded adapter plug, an adapter rail section, and an attaching hex-socket bolt with lock washer.

Will it work on a standard AR-15 lower with an MCX upper? No, it is not intended for that combination.

Buy the KNS Precision AR/MCX Stock Adapter Without Flange

Order this KNS Precision adapter from KNS Precision through our AR-15 buffer systems lineup. It ships fast from our Lubbock, Texas gun shop, fully insured.