Following military doctrine, the M-16/M-4 family of combat rifles are supposed to be zeroed on a 25 meter range. Most civilian AR rifles also come with directions in the owner's manuals to zero their iron sights at 25 meters. Why do we do this? Well, because that is what our drill sergeants have been teaching us to do for the last 30+ years.
Without getting into a 20,000 word discussion that would lose half our viewers, I’ll try to keep this simple. Purpose of the “25 meter zero” is to match the “300 meter zero” on the weapon. Why 300? That distance was chosen as an optimal distance for combat shooting with an M-16. Max effective range for the Army is 460 meters. Marines train out past that.
So, to hit a 300 meter target, you have to elevate the front of the gun above the target to allow gravity to drag the bullet back down into the target at 300 meters. How high do we elevate the front? We elevate the front of the rifle enough so that the bullet actually crosses the line-of-sight at 25 meters. So, if you are hitting the bull’s eye at 300 meters, you will also be hitting the bull’s eye at 25 meters.
So, the military reverse engineered this, and if you zero at 25 meters, you should technically also be zeroed at 300 meters. Using this method saves the military a lot of time walking back and forth checking targets and only requires a 25 meter range as opposed to needing a 300 meter range. Did you know most Air Force bases only have a 25 meter range? Now think about a Forward Operating Base on a mountain in Afghanistan; do you think they have room inside the wire for a 300 meter range? Nope. So, it makes sense. There are dozens of other reasons for using this method of zeroing, but I don’t have time for them here.
With a 25/300m zero, you can just hold on target out to 300 meters, and then dial up the rear sight 4/5/6 to match the distance out to 600 meters. Works great, in theory, if you are shooting at the middle of a 40 inch tall plastic target. I say that because, at around 175 meters, the bullet is a foot over the point of aim. Again, fine for shooting at the center of a 40 inch tall target.
However, how about when you are shooting at a Skinny who is poking his head and AK-47 over a wall at 175 meters? Your target is now only 10 inches tall and your 300 meter zero has your bullet flying 12 inches high. You miss.
This is why many units are switching to a 50 meter zero, when they know they are going to be engaging targets within 250 meters. If you elevate the front of the gun to hit at 200 meters, you are not raising it as much as you did to hit at 300 meters. Therefore, it no longer crosses your line-of-sight at 25 meters, but further down at 50 meters. As a 25 meter zero matches the 300 meter; likewise, the 50 meter zero matches the 200 meter mark.
Since we are not elevating the front of the gun as much, we no longer shoot high 12 inches at 175 meters. As a matter of fact, the biggest reason to use a 50 meter zero is that your bullet will not rise more than 5 inches all the way out to 200 meters. It also won’t fall but 5 inches from 200 out to 220 meters. So, from 10 to 220 meters, you can just hold center of his head and you’ll hit the target. Many find this more useful than a 25 meter zero.
With Pros come Cons. The downside of a 50 meter zero, is that the rear elevation knob (calibrated for 3,4,5,6oo meters with a 25 meter zero) is no longer calibrated. It still works but understand that setting it on “400” will no longer hit a 400 meter target. You’ll have to use the “5” to hit a 400 meter target (roughly).
Still, as Phil explains in the video, there is still merit for choosing a 50 meter zero versus a 25 meter zero. So, educate yourself and then make the correct choice for your individual situation and mission. Remember, knowledge is still the best weapon. Strength & Honor, TR.
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6 апр 2017
