How to Mount an Army Optic to an M4A1


For training Tuesday, we are talking about the mounting of optics to Army weapons. Specifically, we are addressing the mounting of the M150 Rifle Combat Optic to the M4A1. The reference for this discussion is M150 RCO TM 9-1240-416-13&P and CCO TM 9-1240-413-13&P.

The first thing that the Paratrooper should do is  check the eye relief for the optic. This is especially important when mounting magnifying optics to the weapon, as eye relief (the distance from the eye to the optic to get an optimal sight picture) is essential for the consistent application of the shot process. To do this, place the optic on the rail first, then check the rail location until you have minimal ‘scope shadow’ around the edge of the optic.

Once that’s done, it’s important to make sure the optic is secured properly to the rail. This is done by applying forward pressure on the rail while tightening the rail mount. For the CCO, its 2 clicks on the torque limiting knob. For the RCO, it’s following the procedures outlined in the TM and this video below.

Mounting your optics properly ensures you retain the zero while it’s mounted to the weapon, and increases the probability of zero retention when the optic is removed and remounted.

#weaponsmastery #zeroyourblaster


This post currently has one response

  • Something I stumbled across that is helpful with getting OCD about your optics positioning as “eye-relief perfect” as possible: shine a flashlight through the front, and then move a piece of paper/cardboard back-and-forth behind the optic. When the light on the card becomes the smallest/most in focus possible, that’s the optic’s eye relief. (I like using a small multi-LED light, since I know that when all the LEDs are non-blurry light circles on the card, that it’s the perfect distance.) Granted, this doesn’t mean that you *can* mount your optic so that your eye will exactly align with that focal point (for starters, it’s obviously only going to be “the best” positioning when shooting from one specific stance), but it is at the very least handy in fine-tuning a low eye-relief scope’s position within its scope rings.

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