ABOUT THE DUO

ABOUT THE DUO

The DUO system developed through multiple design phases beginning in 2022.

Initial validation began with a simple PLA riser mounted to an ADM QD T1 base. The purpose was to establish viable optical centerline height and usable objective diameter at the furthest practical position along an AR-15 upper receiver.

Three primary architectures were evaluated:

• Forward, separate Picatinny riser

• Combination clamp mount

• Bridging spacer

The combination clamp mount offered maximum rigidity but increased weight and cost.
The forward tower provided flexibility across prism models but required height concessions.

Evaluation ultimately identified the Primary Arms SLx 3X and 5X MicroPrisms as optimal for the intended role. The preferred 1.54” prism centerline required a 2.7–3.0” optical centerline for a piggyback T1-pattern red dot.

A parallel spacer concept was evaluated within an M14 sight pocket. While the 5X prism is not ideally suited to that platform, it served as a useful test case for traditional systems lacking a mature Picatinny ecosystem.

Subsequent revision refined spacer geometry and introduced a contoured sunshade that resolved both optical and physical integration concerns. That revision became the production configuration.

DUO with a 5X MicroPrism (1.54”) and a Holosun ARO-CORE-RDS-2 (2.9”), with a combined mass of 474g (16.75 oz)

DESIGN OBJECTIVES

The DUO system is engineered to:

• Enable cost-effective optical stacks using proven mid-tier optics

• Prevent objective lens glint without reliance on honeycomb ARDs

• Allow rapid lens clearing in adverse weather

• Achieve the lowest practical RDS centerline relative to the prism

• Maintain preferred prism placement on AR-pattern carbines

• Support clamped red dot sunshades (#5-40 front threads)

• Integrate with factory bases and common aftermarket mounts

The intent is system optimization for typical shooting contexts.

COST AND WEIGHT CONTEXT

Optics

Primary Arms SLx 5X MicroPrism — ~$400, ~7 oz
Holosun 403/503/ARO, Vortex Crossfire II — ~$120–220, ~3 oz
Griffin Armament GPS1X — ~$345, 6.3 oz

Parallax System

Spacer, shade, and hardware — ~$200, ~5 oz

Total Stack Weight

~14.6–19.7 oz depending on configuration (without front shade)

COMPARISON TO ACOG SYSTEMS

The 5X configuration aligns most closely with the Trijicon TA55 (5.5×50) and TA02 (4×32 LED).

For reference:

TA55 — 25.6 oz
~$1,700 street / $2,328 MSRP

TA02 — ~17.5–18 oz
~$1,200+ street / $1,750 MSRP

A comparable DUO 5X configuration totals approximately $800, offering significant cost reduction and weight savings relative to a TA55-based stack.

GPS1X-based configurations come under $1,000 and the heaviest stack (GPS1X + shaded 3X) weighs 19.7 oz.

DUO Prototype in field use, January 2026