Sig Sauer X-Fold 1913 Interface Folding Knuckle Stock Adapter

• 1913 interface mount: Attaches to a MIL-STD 1913 rail, making it a practical way to add a folding stock interface to compatible platforms without changing the core receiver layout.
• Folding knuckle design: The foldable construction helps reduce overall length for transport and storage while keeping the stock ready for rapid deployment when the rifle is in use.
• Steel construction: A steel body gives the adapter the rigidity needed at a high-stress connection point, helping the stock feel more secure under repeated handling and recoil.
• Competition to tactical use: Built for competition, general, and tactical applications, it suits rifles that need a compact transport profile without giving up a stable rear stock mounting point.
• Low-profile black finish: The black finish blends easily with modern rifle builds and keeps the adapter visually consistent with common chassis, receivers, and stock assemblies.

About the X-Fold Series

The SIG SAUER X-Fold series is built around a simple idea: give compatible rifle platforms a compact folding stock interface without complicating the rear mounting system. Within the brand's accessory lineup, these adapters and stock interface components are aimed at shooters who want a more transport-friendly rifle configuration for general range use, competition setups, and tactical applications. Rather than functioning as a stock on their own, X-Fold components serve as the mechanical link between the firearm and a folding rear assembly.

The series centers on a 1913 rail interface, a format widely used on modern rifles and chassis systems because it allows modular stock attachment with minimal permanent modification. That makes the X-Fold concept especially relevant for platforms that already use rear rail mounting points or for builds that need flexibility when selecting stock geometry. The design emphasis is on secure lockup, straightforward installation, and reduced transport length when folded. In practical terms, the X-Fold family suits shooters who want a durable hinge assembly that keeps the rifle easier to store, move, and stage while preserving the benefits of a shoulder stock when deployed.

About the Sig Sauer X-Fold 1913 Interface Folding Knuckle Stock Adapter

The Sig Sauer X-Fold 1913 Interface Folding Knuckle Stock Adapter is a purpose-built rear stock interface for rifles that accept a MIL-STD 1913 rail at the back of the receiver. Its role is straightforward but important: it creates the hinge point that allows a compatible stock assembly to fold, making the rifle more compact for transport, storage, or movement in confined spaces. For shooters building a practical field rifle, a compact competition setup, or a tactical carbine, that reduction in overall length can make the firearm easier to case, carry, and stage.

The adapter uses a steel construction, which matters because the folding knuckle sits at a structural point that sees repeated opening, closing, and shoulder pressure in use. A rigid material at this junction helps maintain a more solid feel once the stock is deployed. The foldable design is not just about convenience; it also helps preserve handling flexibility on rifles that may need to transition between transport and firing configurations quickly.

Because this model uses a 1913 interface, it fits naturally into modern modular rifle systems where rear rail mounting is already part of the platform design. The black finish keeps the adapter visually unobtrusive on contemporary builds. Overall, this adapter is best understood as a compact, durable connection component that supports a cleaner folding-stock setup rather than as a cosmetic accessory.

About Sig Sauer

SIG SAUER traces its origins to a wagon factory opened near the Rhine Falls in Switzerland in 1853. Today, SIG SAUER, Inc. is headquartered in Newington, New Hampshire, and the company produces a broad range of shooting equipment that includes firearms, electro-optics, ammunition, airguns, and suppressors. That breadth matters because it gives SIG SAUER practical experience across complete weapon systems rather than in a single product niche.

In the optics field, the company offers riflescopes, red-dot sights, and rangefinders, alongside firearm components and accessories that support modern sporting and tactical platforms. This combination of firearms and electro-optics expertise is relevant to products such as stock adapters, where compatibility, durability, and integration with modular rifle systems are central to the design.

Main Features

• Manufacturer: Sig Sauer
• Material: Steel
• Color: Black
• Foldable: Yes
• Application: Competition, General, Tactical

Warranty

The Sig Sauer X-Fold 1913 Interface Folding Knuckle Stock Adapter is covered by a 2-year warranty.