Ok so first off let me just apologize for taking so long to get back to this. I’ve had a lot of shit going on and I know no one reads this but just in case someone is, I’m sorry for dropping off the planet for a bit. Anyway, let’s get into the topic. This will be a discussion on zeroing your rifle. But first, you’ll need a little preliminary information.
When we refer to Point of Aim (POA) that means where you held your sights for a given shot. Point of Impact (POI) is where the round struck the target regardless of your POA. The goal of shooting is to have the POI be where you intended for it to be. You may be able to have your POA be the same as your POI depending on how far away the target is, or you may have to adjust where you aim to get the desired POI.
Accuracy is a measure of how close your POI is to where you actually intended for the round to hit.
Precision, which is what all the previous entries of this blog have been trying to encourage, is related to how repeatable your shots are. That is, how “tight” your shot groups are.
You can have accuracy without precision and you can have precision without accuracy. But your goal from here on out in learning to shoot will be to combine them and achieve both.
Why would the bullet strike a different point on the target other than where your POA was? To understand that, we need to have a very simplistic understanding of ballistics.
It might surprise you to find out that the flight path of a projectile after it leaves the muzzle of your gun isn’t a straight line. It shouldn’t surprise you when you consider that gravity immediately begins to have an effect on the bullet the second it leaves the muzzle. So what that tells you is that a bullet starts to fall immediately after it leaves the barrel. So how does it even hit the target, let alone hit where you want it to?
It’s difficult to see in real life, but you need to understand that when you fire a round, your rifle will be pointed at a very, very small upward angle. You won’t notice it. You probably won’t even be able to see this unless you’re really looking for it. But, it’s true. The way your sighting system works, be it iron sights or a red dot or a scope, is that it ensures that there is a slight upward angle when the shot is fired. Since the rifle is at a very slight upward angle, the bullet leaves the muzzle traveling in an upward direction. And since gravity immediately makes the bullet start to fall, the result is that a bullet’s path takes the shape of an arch. (Arrows do this too, hence the words archery and archer…)
So the idea is to adjust your sights so that for a desired distance, your POA equals the POI of the shot. When that is the case, you can say your rifle is “zeroed” for whatever distance it is that satisfies that relationship.
What this means is that if I place my front sight right in the center of a target that’s 50 yards away and the round hits the target right in the center of that target at 50 yards away my rifle is zeroed for 50 yards.
This will not just happen. You may coincidently have a rifle that’s zeroed for whatever distance right out of the box. But, more than likely you’re going to have to make the adjustments yourself so we’ll talk about how to do that.
I’d imagine at this point you’re wondering what distance to zero at and how to adjust your sights to do so. So let’s get into the procedure for this. We’ll need to introduce one more technical concept to make the discussion easier. I’m going to short change you on that definition for now but I’ll make the next entry a better explanation of it because it’s pretty important.
Minutes of Angle, or MOA, is what I’m talking about. For now, let’s just think of it as 1 inch per 100 yards. To say that is an oversimplification of this concept is the understatement of the century but for now it’ll help us get through this discussion.
So to clarify, 1 MOA at 100 yards is 1 inch. So at 300 yards 3 MOA would be 9 inches. At 25 yards, a half inch is 2 MOA. Got it? Good!
The reason I bring this up now is to talk about some considerations for your particular rifle and optic. Adjusting your front sight might be a change of 1 MOA, or maybe ½ MOA. Your red dot might also change by ½ MOA per click for example. I don’t know. You’ll need to figure that part out. The paperwork that comes with your red dot should tell you, or it may be printed on the knobs that adjust windage or elevation. Find that part out yourself since there isn’t a standard value.
For our purposes here, let’s assume that we’re zeroing a rifle with iron sights. And let’s assume that each click equates to 1 MOA. (A click is one movement of your sight’s adjustment knob. For the front sight, there will be a mechanism that you’ll need to depress in order to rotate the sight post called a detent. Typically rotating the front sight post clockwise will cause the sight to move down.)
Hopefully you can shoot a tight enough group at this point to be able to zero your rifle. Let’s assume you can. You’re ready to zero this thing. You go out to the range and shoot 5 shots at a target that’s 50 yards away. Your POA was at the center of your target and your shot group is concentrated 2 inches above the bullseye and 2 inches to the left as well. So, diagonally the shots are all 2 inches up and to the left. So you need to bring your shot group 2 inches to the right and 2 inches down. How do you do this?
What is 1 MOA at 50 yards? ½ inch? Correct! So how many MOA is this shot group off from center of the target? 4 MOA up and 4 MOA to the left? You got it! We said each click is 1 MOA. So we adjust our front sight to make the shots go down 4 MOA. So 4 clicks. Here’s where it can get a little tricky when you’re new to this.
For the AR platform, your front sight adjustments will change elevation, and the direction you move it will cause the POI to move in the opposite direction. If I move the front sight down, the POI of my shots will go up.
If we want to move the POI down 2 inches at 50 yards, and we know this is 4 MOA and requires 4 clicks, we now know we need to move the front sight up. They make sight adjustment tools but for an AR front sight you can just use a round. Use the tip of the bullet to depress the detent and rotate the front sight post 4 clicks in the counter-clockwise direction. You might see a curved arrow in a direction on your front sight that says “UP” but the direction is clockwise. That “UP” is saying that the bullet will go up, not the front sight. Remember, there’s an opposing relationship here. YOU MOVE THE FRONT SIGHT THE OPPOSITE DIRECTION YOU WANT TO THE BULLET TO GO.
What about left and right, or windage, adjustments? This is what your rear sight governs. So let’s assume one click is one MOA again. (It probably isn’t, you’ll need to look that up. I’m just trying to make the math easier.) For the rear sight, the adjustments are the same direction for POI change. So in the above example, we wanted to move the shot group to the right 4 MOA. So find the knob that adjusts your rear sight, probably on the right side of it, and move the rear sight four clicks to the right. There will probably be some visual aid on the sight itself to tell you which direction to turn it.
FRONT-OPPOSITE, REAR-SAME. F-O-R-S. This is how you can remember it.
So after you make those adjustments you should find that your shot group’s POI now equals your POA. When this is true your rifle is zeroed at 50 yards. The process to zero with a scope or a red dot is similar, except you have two knobs to adjust instead of front and rear sights. One knob will be for windage, the other will be for elevation. Typically it’ll tell you which direction to turn to get the adjustment you want and what the click value (how many MOA per click) is. Just use the one inch per hundred yards thumbrule and adjust as we did in the examples above for now. We’ll get a better understanding of what MOA actually is next time. I’ll also make an appendix on zeroing an AK when I have time. The main difference on the AK or SKS platform is that the front sight can be adjusted to change both elevation and windage. You’ll need a certain tool to zero it. Moving the rear sight will only cause elevation changes and you’ll use it to account for targets at different ranges. This is one of the reasons I don’t like AKs as much. What if you lose the tool in the field and no one else has one? As long as someone has ammo you can zero your AR.
Anyway, back to the discussion at hand. What distance should you zero your rifle at? Ultimately, it’s up to you. I used to zero at 36 yards, which due to the flight path of the projectile also was pretty damn close to being zeroed at 300 yards. The bullet’s path is an arch so for a lot of cases there will actually be two zeroes. The 36/300 yard zero and the 50/200 yard zero are popular and are useful. Lately we’ve been using the 100 yard zero on our rifles and are finding it really nice to work with. The biggest reason is that the holdovers are easy to learn and you only have to hold high to get the hit you want. With the 300 yard zero there are times when you’d have to hold high and sometimes you’d have to hold low. There’s another concept that’s beyond the scope of this write up pertaining to zeroing called maximum point blank range. You can look into that on your own if you want. It’s a cool concept but I still prefer the 100 yard zero. But, whatever distance you do decide to zero your weapon at, the MOST important thing is that you learn your holds and practice them. Your goal should be able to make accurate hits from 0-400 yards. And you should be able to shoot 2 MOA groups at each of those distances. That’s what I’d recommend personally.
So let’s recap:
I stole the above images from other sites.
Know your rifle’s click value.
Know that the projectile travels in an arch and why.
Know what distance you want to zero at.
Be able to shoot a 2 MOA group. Use at least 5 shots per group when zeroing.
Know what MOA means (even the simplistic definition we used here will work for now.).
When you’re zeroed and can be both precise and accurate, learn your holds for close up and far away and practice, practice, practice.
When making sight adjustments, use the F-O-R-S for the AR platform.
I think that’s about everything we covered. Take care comrades. Hopefully it won’t be so long between entries next time.