There have been thousands of hours spent discussing and even arguing over what everyone considers the best “zero” for a rifle. Zero is the point of which the path of the bullet intersects with the shooter’s line of sight. A common myth is that a bullet flies in a straight line and that simply isn’t true. As a bullet is fired from the end of a barrel it travels in an arc until it is finally stopped by something, either an object or the ground. Throughout this “arc” or path of travel, the bullet will pass through two locations at the shooter’s line of sight. There are benefits and disadvantages of all possible “zeros.” Shooters all have their preferences but the 36 yard zero is the most accurate and easy to use battle ready rifle zero.
The first thing to know and understand is that every rifle and every ammo will produce slightly different results. To know the exact points of impact, the shooter will have to use their own rifle and ammo to record their own results. With that being said, the numbers for bullet rise and drop are approximate (based on 55 grain M855 ammo) but actual results will be still be similar when shooting from a 16-inch barrel.
There are two easy ways to sight in at this 36-yard point. Sight your rifle in at ½ inch low at 25 yards or dead on at 36. The advantages of this zero is that a shooter can accurately shoot out to 400 or even 500 yards without adjusting their sights. They will just be required to remember a few hold over distances. A rifle that is shooting dead on at 36 yards will be hitting about 3.5 inches high at 100 yards, just shy of 6 inches high at 200 yards, dead on again at 300, and around 15 inches low at 400. To simplify this, a shooter can hold directly on center mass of a target out to 300 yards and after that, aim a little high.
The front sight post on an AR can help with finding your target’s range as well. The front sight post is based on 4 moa. Moa is “minute of angle” and used by long range shooters to adjust for wind and distance. 4 moa at 400 yards is approximately 16 inches, which is the average area of a silhouette shoulder to shoulder. If the shooter looks at their front sight post and the post is wider than the area across the silhouette target, they can simply aim at center mass. If the silhouette is wider than the front sight post, the shooter needs to use a hold over. Sweet, simple, and effective.