Folks commonly zero their optics at ranges from 100 to 300 meters (or yards). But not everyone has convenient access to ranges that will allow them to shoot out to this distance. Plus at those distances, if your optic requires some significant adjustments to get dialed in, your impacts might be quite far off at first, making for a very frustrating session. The target included with Issue 9 (you can download it here) is brought to you by Trijicon and is designed to let you approximate a 100, 200, or 300 meter zero even when shooting at 25, 50, or 100 meters.
Bullets do not travel in a straight line like a laser beam; they are subject to the laws of gravity just like anything else. Your rifle’s barrel actually points upward relative to your line of sight. So once a bullet goes straight out of the bore and departs the muzzle of the weapon, it follows an arc, traveling up then down again like a football thrown across a field. When you zero your rifle with a particular load, you are adjusting the optic such that the point of aim equals the point of impact at a particular distance. Because the bullet arcs up and down, the point of impact will intersect with the point of aim at two distances (e.g. at about 50 and 200 meters, or about 30 and 300 meters), except for a 100 meter zero, for which the point of aim is at the crest of the trajectory. Please see the bullet trajectory diagram to get a better sense of this. We can also predict the approximate trajectory your bullets will follow. So, we can mark on the target where your bullets will impact at any given distance even if you are zeroed at a different distance. This is what will allow you to approximate a 100 meter zero at 25 meters.
In truth, though, many factors shift this delicate equation for each one of your rifles, including different ammunition, different temperature, different altitude, among others. All these things (and more) will cause your point of impact to change, even if you aim in the same spot. At extended ranges, these variances get really large but at shorter distances, not as much. Thus we can get you close, so that you can more easily refine your zero at your desired distance when you’re able to get to a longer range.
The new Trijicon VCOG 1-6x scope has a ballistic reticle to allow you to quickly engage targets at various distances without having to memorize a bunch of data. It’s intended to be zeroed at 100 meters and available with reticles specifically designed for 5.56mm, 7.62mm and 300 BLK. Once zeroed, you can use the markings on the reticle to holdover for targets at extended ranges. The included target is calibrated to match up with the 5.56mm versions of the VCOG. The 55-grain VCOG reticle is calibrated for M193 ammo and the 77-grain variant for Mk262 ammo, both assuming a barrel length of 16 inches, temperature of 59 deg Fahrenheit, barometric pressure of 29.92 in Hg, and an altitude of 600 ft.
- If you are at a 25 meter range, use the top left target. Aim at the bullseye and shoot a group. Examine where your bullets are impacting the target and adjust the turrets to dial your impacts to hit where denoted by the applicable marking. For example, if you want a 100 meter zero (with either 55-gr or 77-gr), your impacts should hit approximately 1.6 inches below the bullseye. If you have 55-gr ammo and want a 200 meter zero, they should hit about 1.3 inches below the bullseye. A 300 meter zero with 77-gr ammo should actually pretty much hit the bullseye. The same principle applies for other combinations of ammo and desired zero distance, which are marked on the target.
- If you are at a 50 meter range, use the bottom left target. Aim at the bullseye and shoot a group. Examine where your bullets are impacting the target and adjust the turrets to dial your impacts to hit where denoted by the applicable marking. If, for instance, you want a 100 meter zero with 55-gr ammo, your bullets should hit about 0.8 inches below the bullseye, but for a 200 meter zero, they should hit the bullseye. For a 300 meter zero, your impacts will be rather high above the bullseye, approximately 2.3 inches high with 77-gr and 1.5 inches with 55-gr ammo. Use the other markings as applicable to dial in your zero with other combinations.
- At a 100 meter range, use the targets on the right half of the target. Naturally, for a 100 meter zero, simply aim at and adjust your hits to the bullseye. For 200 or 300 meter zeros, you will hit high, so adjust your scope to hit at the appropriate markings above the bullseye.
- Please be sure to verify your zero at your actual desired distance as soon as you can.
So, to summarize, select the target which matches your range (25m, 50m or 100m), always aim at the bullseye, and dial your impacts to match the offsets shown on the target to correspond with your ammo and desired zero. While calibrated for the Trijicon VCOG with M193 and Mk262 ammo, the markings on the target can be used for other combinations that have roughly similar trajectories.
Also, please note the adjustment notations (up, down, left and right) at the corners of the target, which remind you which direction to dial your turrets. For example, if your bullets are hitting below and to the right of where you want them to hit, look in that corner of the target and you’ll be reminded to dial your turrets up and left. If bullets are hitting too high and too far left, look at the top left corner and note that you need to dial down and right.