FAQ
What is the HDA3?
The HDA3 is a modular stock/brace system developed from a collaboration between Haga Defense and A3 Industries. The HDA3 was designed specifically to integrate seamlessly across dozens of firearm platforms without sacrificing strength or aesthetics to do so.
When will the HDA3 be available?
The HDA3 was quietly released on March 24, 2025. The highly anticipated release was not announced in order to be fair to those that have been on the in-stock email notification lists the longest. The best way to find out when an HDA3 for your firearm will be available is to sign up to be notified by email when in stock. You can do this on the product page.
Are the HDA3s from Haga Defense and A3 Industries different?
The core HDA3 stock and brace components will be exactly the same no matter where you get them from but the firearm specific adapters may be different. For example a Bren 2 stock adapter from Haga Defense may have QD sling attachment machined into the aluminum where the A3 Industries variant will have a steel QD socket set into the aluminum adapter. Or the MP5 adapter from A3 Industries will be nylon while the adapter from Haga Defense will be aluminum. Be sure to check out both Haga Defense and A3 Industries to see all available options. Some options may be available on both websites and some only on one or the other. You can use the part number to identify which adapter a stock or brace has.
Example:
HDA3-MP5-HD-S-LF-BLK - Haga Defense
HDA3-MP5-A3-S-LF-BLK - A3 Industries
How do you fold the HDA3?
To fold the stock, grasp the stock placing your thumb over the top of the folding hinge. Press down with your thumb while lifting up on the stock to dislocate it. This will allow the hinge to fold. Hinges may be pretty stiff to operate when new. They will break in and become easier to operate over time with use.
Will the HDA3 be available in a right folding option?
The HDA3 will initially only be available with a left folding option. Right folding options are planned to be available at a later date as well as kits to convert left folding stocks to right and vice versa.
Will the HDA3 be available in more colors?
The initial release will be black only. FDE, ODG and Gray will follow shortly after. No other colors are currently planned.