The Sylvan Arms Arh400-L Gen4 folding stock adaptor transforms your AR-platform rifle into a compact, packable system without sacrificing functionality. Built for hunters, overlanders, and shooters who need a rifle that breaks down for vehicle storage, travel, or tight-quarters deployment, this folding stock adaptor uses a simple mechanical design to collapse your buttstock down the length of the receiver. The Gen 4 design sits closer to your AR lower receiver, minimizing gaps and reducing overall length when folded—exactly what you need when space is at a premium.

Machined from 7075 billet aluminum, the Arh400-L weighs just 6.0 ounces and resists corrosion without adding bulk. Sylvan Arms engineered this adaptor to work with standard AR15 1-3/16" x 16-thread stocks and most bolt carrier groups with no additional modifications required. The critical difference between left and right fold options: choose based on your preferred fold direction (right fold aims toward the ejection port; left fold folds away from it). Installation is straightforward—the included castle nut wrench handles the job, and you don't need to disassemble the adaptor or your BCG to get it mounted. All hardware needed for install comes in the box.

Compatible across most AR platforms including .223/5.56, .308, 300 Blackout, and many 9mm builds (those with standard 5/8 ID bolt carriers), the Arh400-L also includes a .625 aluminum bolt extension for certain 9mm applications. Note that it does not work with Tippmann 22 or LWRC pistol platforms. Whether you're building a truck gun, travel rifle, or compact setup, this made-in-USA adaptor gives you genuine folding functionality without the complexity.

The Sylvan Arms Arh400-L Gen4 folding stock adaptor transforms your AR-platform rifle into a compact, packable system without sacrificing functionality. Built for hunters, overlanders, and shooters who need a rifle that breaks down for vehicle storage, travel, or tight-quarters deployment, this folding stock adaptor uses a simple mechanical design to collapse your buttstock down the length of the receiver. The Gen 4 design sits closer to your AR lower receiver, minimizing gaps and reducing overall length when folded—exactly what you need when space is at a premium.

Machined from 7075 billet aluminum, the Arh400-L weighs just 6.0 ounces and resists corrosion without adding bulk. Sylvan Arms engineered this adaptor to work with standard AR15 1-3/16" x 16-thread stocks and most bolt carrier groups with no additional modifications required. The critical difference between left and right fold options: choose based on your preferred fold direction (right fold aims toward the ejection port; left fold folds away from it). Installation is straightforward—the included castle nut wrench handles the job, and you don't need to disassemble the adaptor or your BCG to get it mounted. All hardware needed for install comes in the box.

Compatible across most AR platforms including .223/5.56, .308, 300 Blackout, and many 9mm builds (those with standard 5/8 ID bolt carriers), the Arh400-L also includes a .625 aluminum bolt extension for certain 9mm applications. Note that it does not work with Tippmann 22 or LWRC pistol platforms. Whether you're building a truck gun, travel rifle, or compact setup, this made-in-USA adaptor gives you genuine folding functionality without the complexity.