Description
HDA3 Folding Stock for HK91, G3
The HDA3 is a modular, USA-made stock system developed by Haga Defense and A3 Industries. Built for strength, adaptability, and cross-platform compatibility, it delivers premium rigidity, smooth adjustability, and long-term durability.
Features:
- Folding Steel Hinge: Heavy-duty steel hinge locks solidly in both open and folded positions. Folds left at a 3.5° cant.
- Reinforced Construction: All-metal internal components, including an aluminum cheek-riser button and length-adjustment latch, integrated into an extruded aluminum spine secured to the steel hinge.
- Adjustability: Length adjusts in 0.5″ increments across 7 positions. Cheek riser offers 3 positions (0, +0.25″, +0.50″). Both are one-hand operable.
Specifications:
- Material: 6061 hard-coat anodized aluminum adapter
- Polymer Components: 30% glass-fiber reinforced nylon
- Adapter Dimensions: 2.625″ H × 1.5″ W
- Buffer: Choate buffer included
- Length: 7.91″–10.91″
- Hinge: Nitride-coated 17-4 stainless steel, left-folding
- Extension: 7-position 6061 aluminum extrusion with 7075 locking latch
- Cheek Riser: 3-position polymer riser with anodized aluminum button
- Buttpad: Textured Santoprene TPE (stock configuration)
- Sling Mounts: Rear sling loop, two steel QD points on the stock, plus three QD mounts on the adapter
Compatible With:
- HK91, G3
- Rifles using the same style end cap (PTR91, PTR-PDW, HK33, HK53, HK93, etc.)









