SYLVAN ARMS AR15 AR9 LH FOLDING STOCK ADAPTER

The Sylvan Arms AR15/AR9 left-hand folding stock adapter is a purpose-built solution for shooters who need a compact, maneuverable platform without sacrificing strength or reliability. Built in the USA from CNC-machined 4140 steel, the SA5 gen adapter delivers 250% more strength than its predecessor while weighing just 9.4 ounces—light enough that it won't noticeably burden your rifle, yet robust enough to handle hard use. Whether you're setting up a truck gun, working in tight spaces, or simply want a more packable AR, this left-fold adapter screws on using standard 1-3/16 x 16 threading and locks into place with an improved mechanism that won't rattle or fail.

Installation takes under five minutes and requires no gunsmithing—Sylvan Arms includes all necessary tools and a 1045 steel bolt extension in the box. The included extension lets you run most 9mm bolt carriers (standard 5/8 ID sizing) after a simple pin and weight removal; standard AR15 carriers work without any modification. Adjustable hinge tension lets you dial in the fold resistance to your preference, while dual QD attachment points give you options for sling mounting or accessories.

This adapter is compatible with .223/5.56, .308, 300 Blackout, and most 9mm AR platforms. Note that it does not work with Tippmann 22 or LWRC pistol-caliber builds. The user-serviceable design means you can maintain or adjust it in the field without sending it back to the manufacturer—a practical feature for serious shooters who demand independence from their gear.

Key Features

• CNC-machined 4140 steel, USA-made construction
• Left-fold configuration for southpaw shooters and left-side carry
• 250% stronger than previous generation adapter
• Only 9.4 ounces—minimal weight penalty
• Adjustable hinge tension for custom fold resistance
• Improved hardened buffer pin and locking mechanism
• Dual QD attachment points for versatile mounting
• Includes all installation tools and 1045 steel bolt extension
• Installs in under 5 minutes with no additional parts required for standard AR15 BCGs
• User-serviceable design

Specifications

Frequently Asked Questions

What AR platforms is this left-fold adapter compatible with?

The Sylvan Arms SA5 works with AR15 and AR9 platforms chambered in .223/5.56, .308, 300 Blackout, and most standard 9mm ARs. It does not work with Tippmann 22 or LWRC pistol-caliber builds. For 9mm bolt carriers with standard 5/8 ID sizing, you'll need to remove the pin and weight from the rear of the bolt carrier group and install the included bolt extension.

Do I need to buy additional parts or tools to install this adapter?

No. The adapter comes with all necessary installation tools and a 1045 steel bolt extension, so you have everything needed for a complete install. Standard AR15 bolt carrier groups require no modification—just thread it on and fold. For compatible 9mm carriers, the only step beyond installation is removing the pin and weight from the BCG rear before inserting the included extension.

How much does the folding adapter add to the weight of my rifle?

The SA5 adapter weighs just 9.4 ounces, making it one of the lightest folding solutions available. For comparison, this is significantly lighter than traditional fixed stocks, so folding your rifle results in minimal overall weight increase.

Can I adjust how tight or loose the folder folds?

Yes. The SA5 features adjustable hinge tension, so you can customize how much resistance the stock encounters when folding and unfolding to match your preferences and use case.