Sig Sauer MCX Stock Adapter Kit

• MCX-to-AR compatibility: This adapter kit lets an AR-15 lower accept a SIG SAUER MCX or MCX-LT upper receiver group and stock assembly, making it useful for builders who want MCX functionality on a familiar lower platform.
• Designed for SIG folding stocks: The kit is made to work with SIG SAUER MCX and MCX-LT stocks, helping maintain proper fit and operation when configuring a rifle around the MCX system.
• Complete core adapter set: With the rail attachment, bumper housing, recoil bumper and shoulder screw included, the package provides the key parts needed for the conversion rather than leaving critical hardware to be sourced separately.
• Compact, durable construction: Its black finish and purpose-built metal components suit hard-use rifle builds while keeping the installation visually consistent with modern tactical platforms.

About the Sig Sauer Accessories Series

Sig Sauer Accessories covers a broad support range built around the company’s firearms and electro-optics platforms. Rather than focusing on a single category, the series brings together mounting solutions, part kits, tools, slings and protective accessories for rifle optics, handgun optics, binoculars and rangefinders. That wide scope makes the line especially relevant for shooters who want to keep a platform consistent across setup, transport and field use.

Within the series, SIG SAUER includes practical items such as mounting plates, screws, lens covers and flip-back caps, alongside maintenance products and more specialized interface parts. The design approach is straightforward: accessories are built to solve platform-specific fitment and handling needs without unnecessary complexity. In practice, that means the series serves everyone from recreational rifle owners to users assembling more specialized hunting optics or tactical optics setups, with products that support compatibility, protection and day-to-day usability.

About the Sig Sauer MCX Stock Adapter Kit

The Sig Sauer MCX Stock Adapter Kit is a rifle interface component made for shooters who want to configure an AR-15 lower to accept a SIG SAUER MCX or MCX-LT upper receiver group and stock assembly. Its value is practical rather than cosmetic: it helps bridge two platform architectures so a build can take advantage of MCX-style stock compatibility while retaining the lower receiver already in use.

This kit is intended for use with SIG SAUER MCX and MCX-LT stocks, which is important for maintaining the intended fit and operating geometry of the system. For builders, that means a more predictable setup when pairing the lower with a compatible upper and stock assembly. The included parts package consists of a rail attachment, bumper housing, recoil bumper and shoulder screw, giving the user the core hardware required for the adapter installation in one set.

Finished in black and built as a dedicated rifle part, the adapter suits modern sporting and tactical rifle configurations where clean integration matters. As a platform-specific accessory rather than a universal stock part, it is best understood as a functional conversion component: it supports compatibility, preserves the intended stock interface, and helps turn a mixed-platform rifle project into a coherent working assembly.

About Sig Sauer

SIG SAUER traces its origins to a wagon factory established near the Rhine Falls in Switzerland in 1853. Over time, the company developed into a major firearms maker, and SIGARMS changed its name to SIG SAUER in 2007. Today, SIG SAUER, Inc. is headquartered in Newington, New Hampshire and produces a broad catalog that includes firearms, electro-optics, ammunition, airguns and suppressors.

In the optics field, the company is known for riflescopes, red-dot sights and rangefinders, alongside proprietary technologies used across its product lines. That platform-focused approach is relevant here because SIG SAUER accessories are typically designed around direct compatibility with the company’s own rifles and components, giving users purpose-built parts rather than generic substitutes.

Main Features

• Manufacturer: Sig Sauer
• Series: Sig Sauer Accessories
• Accessory Type: Stock adapter kit
• Compatible With: Rifles
• Color: Black

Warranty

2 years. The Sig Sauer MCX Stock Adapter Kit is covered by a 2-year warranty.

In the Box

• Rail attachment
• Bumper housing
• Recoil bumper
• Shoulder screw