SKU: IQARH400L
UPC: IQARH400L
MPN: ARH400-L
The Sylvan Arms AR15 & AR9 Folding Stock Adapter Gen. 4 Left Fold converts standard AR platform rifles into compact, foldable configurations for easier storage and transport. This left-fold variant hinges away from the ejection port, maintaining clear access to controls and optics. At just 6 ounces, the adapter adds minimal weight while dramatically reducing overall length when folded. We stock this adapter for shooters who need a more portable AR15 without permanent modifications to their lower receiver. The Gen 4 design threads directly onto standard 1-3/16" x 16 buffer tube threads found on most AR15 and compatible AR9 builds.
Sylvan Arms machines this adapter from 7075 billet aluminum in the USA, the same aerospace-grade alloy used in mil-spec receivers. The Gen 4 revision sits closer to the AR lower than previous generations, reducing the gap between adapter and receiver for a tighter overall profile. The adapter works with standard AR15 bolt carrier groups without requiring additional parts, and it ships with JP Enterprise Silent Capture Buffer Spring compatibility built in. An included wrench simplifies installation, letting you swap between folding and fixed configurations as needed. The standard threading means this adapter integrates with your existing buffer tube and stock combination—no proprietary components required.
This folding adapter suits truck guns, backpack builds, and any scenario where a 30-inch carbine becomes a storage problem. Law enforcement and security professionals use these adapters for discrete vehicle carry, while hunters appreciate the packability for backcountry transport. The left-fold orientation works particularly well for right-handed shooters who want the stock to clear their support hand during deployment. Pair this adapter with a compact stock from our selection, or browse our complete rifles category if you're building from scratch. Sylvan Arms backs this adapter with a limited lifetime warranty.
No. Like most folding stock adapters, the Sylvan Arms Gen 4 requires the stock to be extended and locked for firing. The buffer tube must be inline with the receiver for the bolt carrier group to cycle properly. The folded position is for transport and storage only.
The left fold version hinges the stock to the left side of the rifle, away from the ejection port on standard AR15s. This keeps the folded stock clear of brass ejection and right-side controls. Right fold versions hinge toward the ejection port side.
Sylvan Arms indicates compatibility with most AR15s and some AR9 platforms. AR10 and 308 AR rifles typically use different buffer tube threading and longer buffer systems. Check your specific lower receiver threading before purchasing for larger caliber platforms.
The adapter includes a wrench for installation. You'll also need a castle nut wrench or armorer's tool to remove your existing buffer tube. Installation threads onto your lower receiver's standard buffer tube threads—no permanent modifications required.
Yes. The Gen 4 adapter works with JP Enterprise Silent Capture Buffer Spring systems directly out of the box. Standard mil-spec buffer tubes, springs, and weights are also compatible with the adapter's pass-through design.
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