A lot of rifles come with a moderately usable sight that works fairly well under good lighting conditions. But for usability under low light or stressful situations, the ACOG (Advanced Combat Optical Gunsight) possesses some awesome advantages.
While most hunting scopes are fragile, the ACOG is built like the proverbial tank. It’s relatively lightweight and compact and doesn’t require batteries to light up its reticle. That’s taken care of by tritium (hydrogen-three) illumination which has a lifespan of 10 to 15 years. Thus, the aiming point is lit up even in zero-light conditions.
During variable light conditions, fiber optics channel an adjustable amount of ambient light into the reticle, making the ACOG a sight for virtually all lighting conditions.
1. Custom reticle. First of all, realize that if you don’t like the reticle pattern, it can be changed. You will need to contact the manufacturer’s (Trijicon’s) Customer Service Department to discuss the installation of a new prism assembly, but it can be done.
2. Inspect the ACOG. You will want to ensure the reticle works in a dark room, but let your eyes adjust. This should take no longer than a couple of minutes. The reticle is nearly impossible to see in zero-light or extremely low-light conditions until your eyes have acclimated. When ready, simply look through the scope to ensure the reticle is illuminated.
3. Install the ACOG. First, locate the knobs at the base of the clamp assembly. Loosen them. Next, put the ACOG on the flat-top rail. Note that the studs should be aligned within the rail grooves. Finger-tighten the knobs, then include an extra quarter-turn. A 1/4-inch screwdriver is recommended, but this size is not critical. Just use what works.
4. Zero the ACOG. This is accomplished by comparing the reticle’s center to the rifle’s impact point. The recommended method is that of using a boresighter, but the use of live ammunition at a target range should work just as well. Incrementally adjust the scope axis until the reticle’s center matches the rifle’s impact point.
Note that ACOG adjustments come in at 1/4 inch per click at 100 meters. For example, in order to correct the reticle center by two inches at 100 meters requires eight clicks in the appropriate direction. You will find these adjusters on the scope’s top and right side.
Don’t ever force the reticle adjusters. If something is wrong with the scope, applying too much force on the adjusters can harm the internal prism assembly. For further instructions, you should contact the manufacturer.
5. Clean the scope. The “lenspen,” which comes with your ACOG, should be used to remove any dirt from the lens. Use the brush side for this. When clear of all dirt or other material, use the felt side to finish with the lens cleaning.
The sight is virtually maintenance free, but if any part of the ACOG doesn’t work, you should contact the manufacturer right away for instructions. See Lincoln Tacticals “4-Step Guide to Using an ACOG Scope“.