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Sylvan Arms Folding Stock Adapter (ARH300)

Usually ships the same day or the next business day!

Set up your AR-15 to make it more easily stowable when you carry with you to the range. No more carrying around huge bulky rifle bags and cases. Make your rifle short enough to fit into something smaller. Shorten it for travel with the AR-15 and AR-9 Folding Stock Adapter gen 3 by Sylvan Arms. This adapter is easy to install and allows you to "unlock" the stock of your rifle and fold it a position where it rests alongside the receiver of your rifle for a more compact way to take it with you to the range.

And don't worry, it's super compatible. The Folding Stock Adapter installs with no machining or tinkering. It's compatible with standard sized AR platforms, even up to LR-308 and most 9mm sizes. It's simple to install too. If you have an armorer's wrench, you can install it in minutes. And because it's made from 7075 billet aluminum, it only adds 6 ounces to your rifle's weight. See below for more details.

You can access the ARH300 user manual here.


Fit: platforms .223/5.56 to .308 & most 9mm:

  • 9mm bolt carriers with 5/8 ID (.625) standard sizing can use the bolt extension included, after removing the pin and weight from the bolt carrier
  • 17/32 .531 bolt extension for smaller bolt carriers is available here

If your PSA bolt carrier is causing the bolt extension to come up short contact Sylvan Arms for a conversion.

  • Does NOT work with Silent Capture Buffer Springs
  • Does NOT work with JP Enterprise Buffer System
  • 300 blk (blackout) compatible
  • Adds 1.3 inches to Length of pull
  • Surface treatment: hard coat black anodized
  • Material: 7075 CNC-machined billet Aluminum
  • Thread specifications: 1-3/16″ X 16
  • Hinge dimensions: 3 11/16 inches
  • Hinge weight: 6.0 oz, BC – Extension 3.1 oz
  • Hinge length: 1.3 inches
  • Warranty: limited lifetime

Made in the U.S.A. Because 'Murica.

WARNING: Handling firearms parts and accessories can expose you to lead and other petroleum products known to the State of California to cause cancer and reproductive harm. For more information go to:

Shipping Restrictions

Shipping of various parts and/or accessories are prohibited to states and locales (ie New Jersey, California, New York, etc…) with restrictions against certain parts and/or accessories or "assault weapons" (i.e. states with high-capacity magazine restrictions, manufacturing of semi-automatic weapons, etc..). It is your responsibility to be aware of your local firearms laws before purchasing from our website or machining a firearm. We try our best to keep our shipping page current, but laws change daily. only ships within the United States. Federal legislation dictates we cannot ship our products internationally.


We are a national retailer of individual components and not all products depicted on this website are legal in every state. Shipping of various products found on this website are prohibited to some states (such as California, Connecticut, District of Columbia, Hawaii, New Jersey, New York, Rhode Island, and Washington). The information, pictures, text or products presented on this website are not a representation by us, and should not be understood by you, that any product or completed firearm is legal to assemble or own in your state of residence. We encourage each and every builder to perform their own research about the state and federal laws that apply to them. It is your responsibility to understand the law and we encourage you to consult with an attorney or your local ATF representative.