The Bindon Aiming Concept (BAC) is a both-eyes-open aiming method which allows shooters to acquire, track and hit targets more accurately than with one-eye-closed riflescopes.

The TA31RCO is an Advanced Combat Optical Sight (ACOG)
designed for the M16M4 weapon system (14.5 barrel). It provides the shooter with quick target acquisition at close combat ranges while providing enhanced target identification and hit probability out to 800 meters utilizing the Bullet Drop Compensator. The TA31RCO incorporates dual-illumination technology using a combination of fiber optics and self-luminous tritium. This allows the aiming point to be always illuminated without the use of batteries.  The Tritium illuminates the aiming point in total darkness, and the fiber-optic self-adjusts reticle brightness during daylight according to ambient light conditions. This allows the operator to keep both eyes open while engaging targets and maintaining maximum situational awareness. Designed to the exact specifications of the United States Marine Corp, the unique reticle pattern provides the shooter with quick target acquisition at close combat ranges while providing enhanced target identification and hit probability out to 800 meters utilizing the Bullet Drop Compensator.

With its dual-illuminated reticle, the Trijicon ACOG TA31RCO-M4CP provides shooters with a distinct aiming point in all light  conditions – without batteries.  Powered by a tritium-phosphor lamp, the scope’s reticle glows in low-light  conditions, while advanced fiber optics automatically adjust the brightness level and contrast of the reticle in brighter light conditions.  Many models – including the 4x32 ACOG TA31RCO M4CP that’s now available to hunters and target shooters – incorporate the innovative Bindon Aiming Concept™ (BAC). This revolutionary, both-eyes-open aiming method provides you with “instinctive” target acquisition and increased hit potential. And, the scope’s ranging is built into many of its reticles, allowing you to set zero and never worry about it again.  Broad-band, anti-reflective coated lenses provide superior clarity and light gathering capabilities with zero distortion. The ACOG TA31RCOM4CP also offers large eye volume, giving you greater leeway – fore and aft, and from side to side – with which to see through the lens. Of course, once the target is acquired, the ACOG TA31RCO-M4CP is a trusted ally to help you zero in on a perfect shot. 

The ACOG TA31RCO M4CP is crafted with a tough, military-grade aluminum-alloy housing and is waterproof to depths of 328 feet – making it nearly indestructible. Only the prism housing moves, so it’s much more rugged than conventional designs. And the ACOG TA31RCOM4CP does not require failure-prone batteries – so you can rely on it to perform in practically every situation.