American Defense AD-B3 Modular Base



Product Description

The AD-B3 modular base is the largest base in our modular lineup. Standalone it is a mount for the full-sized 3x Power ACOG scopes, such as the TA01, TA11, and TA31. It also fits scopes with similar ACOG Style Bases such as the Burris AR-332 and newer model Trijicon RX-30 optics with 3 inline mounting holes. The overall length of the base is 3.5″. It is precision machined from 6061 T6 aluminum and finished in hard coat T3 Mil-Spec anodize. It features the Patented QD Auto Lock(tm) Lever system to accommodate both in-spec and out-of-spec rail systems.

The washers in the included hardware kit are only to be used for the Sightmark IR scopes (4K, 4K mini, HD, etc)

The AD-B3 Modular base features the Patented QD Auto Lock(tm) Lever system which has the following advantages:

  • Does not require proprietary tools for adjustment.
  • Can be adjusted with your finger or a flat-blade screwdriver.
  • The lever can be configured to lock to the front or the rear.
  • Superior clamping surface to ensure maximum rail engagement.

The AD-B3 Modular base is precision CNC machined from a block of 6061 T6 aluminum and finished in hard coat type 3 Mil-Spec anodize for a rock-hard, long-lasting finish.

  • Precision machined from 6061 T6 Aluminum.
  • Hard coat anodized for a lifetime of performance.
  • Fully adjustable to fit both in-spec and out-of-spec rail systems.
  • American Defense MFG, LLC. products feature a lifetime warranty.
  • Features the Patented QD Auto Lock Lever system.
  • Made with pride in the U.S.A.

The AD-B3 Modular base has the following specifications:

  • Weight: 3.00 ounces




Technical Information

Color / Pattern

Lever Style



6061 Aluminim



Catalog Location

California Prop 65 Warning

WARNING: This product can expose you to chemicals, which are known to the State of California to cause Cancer and Reproductive Harm. For more information visit