Sylvan Arms AR15 Folding Stock Adapter Gen 4

Sylvan Arms' Gen 4 uses a 7075 billet-aluminum body to hold installed weight to 6 ounces. It threads into the standard 1-3/16x16 AR receiver-extension interface and is offered in left- and right-folding versions. Sylvan lists the fit as .223/5.56 through .308 platforms plus most 9mm, and the adapter needs no extra parts with a standard AR-15 bolt carrier group.

The current product page excludes Tippmann .22 and LWRC pistols. Some 9mm bolt carriers also require removal of an internal pin and weight before the supplied .625 bolt extension will fit, so buyers need to inspect the carrier rather than assuming every blowback AR-9 is ready for the same installation.