How to Zero an AR15
Major Pandemic 06.11.13
Giddy as a schoolgirl, you pull your brand new, never-before-fired AR-15 from its case and blast away several magazines worth of ammo on the 25-yard range, making cans dance… Or not. After the first magazine, it’s clear to you that your new AR needs proper zeroing, but what is the best method and zeroing point?
We’ve all seen the person frustrated with each round sent downrange at a 100-yard target, as they futilely attempt to zero their new rifle or optics. You hear their muffled cries as the bolt locks back from yet another empty magazine, while a pristine target still sits down at the end of the range. That guy made his first mistake when he set out to zero his AR with a 100-yard target. The standard military method for zeroing most military rifles, including the M-16/AR-15 rifles, is to zero at close range, and this method will get you perfectly zero’ed in around a dozen rounds.
The military has found that the ballistic trajectory for a typical .223/5.56 Nato round hits the same point of aim at 25 meters and 300 meters with a military spec round, 4”-5” high at 100 yards, 12” low at 400 yards and 36” low at 500. Use this zero and you will be stunned at how simple hitting distant targets becomes. One of the all-time best AR15 25M/300M zeroing targets is the free (yes free) printable, BobDBob.com 25M AR15 Zeroing target (PDF). This target has a grid that gives you the appropriate windage and elevation adjustments.
Use a cheap landscaping tape measure and measure off 25 meters (82 feet) from the muzzle of your AR on the bench to your target. Make sure that you measure it exactly with a ruler or a laser rangefinder, because a couple feet either way will impact the precision of your zero. Also ensure that you are shooting level with the target via a rest, and shoot a three-shot group. If you are not on the paper, you will need to move the target closer, generally the 10-15 yard line, but, in most cases you should see a nice little cluster somewhere on the target.
The BobDBob.com target gives you a grid guide that enables you to make the appropriate number of left or right click adjustments to both the front and rear sights. Making the required sight adjustments should deliver the next three shots on the center black silhouette. Make any minor adjustments and shoot a final group to ensure that your shots are dead center. If no further adjustment is required, then validate the zero at 100M to ensure that you are not a click off on windage left or right.
I am fortunate that at our range, we have a 12-inch, 300-meter steel gong that makes it really easy to validate that a rifle is delivering a 300-meter zero. Three satisfying hits in a row with my AR on the 300M gong puts a smile on my face. If you followed the above steps, then your AR will be properly zero’ed and can easily deliver the same accurate hit out to 300M.