Long-range shooting is one of the most challenging and fun things a sportsman can do with their firearm. Getting a tight grouping at 400 or even 800 yards is something that not many people can do. There are so many factors that affect accuracy at those ranges, including wind, holdover, and even the ammunition you’re firing. However, before you can work on those, you have to address the elephant n the room when it comes to long-range shooting: how well is your scope zeroed in?
Zeroing in, or sighting in your scope should be one of the first things you should do after mounting it, and everyone knows that. But there are other times you should be zeroing that scope in as well. Here are a few times when it’s worth it to take your rifle out and resight it.
- Drops or Impacts – No matter how much care you take with your rifle, accidents happen. Whether it's getting it bounced off the forest floor when your hands are slippery, or a butterfingered handoff as you're going over a fence, a hard drop can whack your scope out of alignment. In most cases, it's worth it to remount the scope just to ensure its vertical alignment is still true to your weapon.
- Traveling – It doesn't matter if you use a hard case or not when you're traveling. Everyone has seen the way that baggage gets handled in transit. Taking an hour to re-zero your scope after you get to your destination is a small price to pay so you don’t miss that 500 yard shot on a trophy elk.
- After You’ve Lent it Out – Everyone has a friend that likes to go hunting but doesn’t own a rifle. And everyone’s been that friend who’s lent out their rifle. While your friend isn’t going to mess with your scope on purpose, you don’t know what’s happened to that gun when it’s out of your sight. So after you give it a good cleaning, take an afternoon and resight it in.
There’s one other time that you should resight your scope, and that’s if you’re using a budget scope or mounts on a high-powered rifle. Everyone’s been there; you’re looking to save a few bucks, and you get aluminum mounts or an inexpensive scope. Trouble is, a few hard recoils, and your scope’s going to shimmy around a bit. If you can’t afford to upgrade, take the time to zero it in before you go back out hunting.
What to Bring With You to the Range
Now that you know when you should sight in your scope, this is the how. Once your scope is mounted correctly and in vertical alignment with your rifle, head out to the range. Here's a list of things you'll want besides your rifle, ammunition, and targets.
- A good set of calibrated calipers – These can be inside or outside calipers, but you want to make sure you’re getting accurate distances for your shot groupings.
- Range finder – You’re zeroing for accuracy at long ranges. If you’re not headed to a reliable range with distances clearly marked, you need to be able to sight things in yourself.
- A Calculator – Not everyone is good with math and that's okay. Bring a calculator or use one on your phone. Just use something to double-check your figures so you're doing it right the first time.
- A Protractor – You can get one of these at the dollar store. You want to make sure that you’re measuring correctly along the vertical and horizontal axes, and a protractor is the best way to make sure of that.
- A sheet of flat plywood a little larger than your targets – You’re going to be making a lot of measurements that require accuracy. That’s going to need a flat smooth surface to plot things out on.
- Sandbags and a gun rest – When firing, your weapon is going to recoil. Giving your weapon a softer surface to rest on will reduce bounce and enhance accuracy. It’s worth it to try out different types of tripods and resting surfaces to find out what is going to absorb the bounce the best. Some people have even gotten the best results using 40-pound bags of cat food as the resting surface.
Also, check your scope’s windage and elevation turrets. If they aren’t finger adjustable, make sure you have the right tools to adjust them in the field.
Before You Start
One of the first things you need to do is correct for parallax. Parallax is a phenomenon when the target image and the reticle are not on the same optical plane. You’ll see this when you’re looking through the scope and wiggle your cheek into the weld and notice the crosshairs dance around the target instead of staying in the same spot.
Thankfully, most scopes designed for long-range shooting have parallax adjustment features. This is a dial that will slowly bring the target and reticle together. Get a good cheek weld on your rifle and sight downrange onto a target. Move your eyes around and slowly turn the parallax turret. You should see the reticle wiggle get smaller and smaller until it stops moving completely.
Now that the parallax is taken care of, you’re ready to actually sight in your scope.
Step One: 25 Yards
First, set a target out at 25 yards. If you are using a variable magnification scope, adjust it so you’re at the highest magnification. Put the crosshairs on the 10 ring and fire three shots. The goal is to get the shots on paper so you can make your initial adjustment. Now bring your target in and lay it flat on your plywood or the shooting table.
Use the protractor to draw perpendicular lines from your bullet holes to the axes on the target. If your target doesn’t have axes, use the protractor to create them. You want your measurements to be as precise as possible.
Once you’ve done that, mark the distances. For example, let’s say that your initial shots land in the upper right quadrant. You measure and find that the shot is 3 inches to the right and 1 inch up.
Checking your scope’s manual, you find that the windage and elevation knobs are set to one-eighth minute of angle (MOA) increments. This would be referred to as eighth-minute clicks. This means that at 100 yards, each click will adjust your shot placement by an eighth of an inch.
As the target gets closer the adjustment gets smaller, and as the target is farther, the shot placement gets larger. For example, at 200 yards, the shot would move one-fourth of an inch, but at 50 yards, it would only move one-sixteenth of an inch.
Some scopes use milliradian (Mrad) adjustments instead of MOA. These scopes are dialed into metric measurements and are calibrated for 100 yards. Most Mrad scopes have 1/10 Mrad adjustments. This translates into 1 cm at 100 yards.
Use this handy chart to get a feel for target distance vs. shot movement.
Windage and Elevation Adjustment Chart
1/4 minute click
1/8 minute click
Using the above example at 25 yards, you would need to move your elevation turret 32 clicks down and your windage turret 96 clicks left. Once you’ve made the necessary adjustments, fire another three shots at your target. Check to see where your shots land and adjust again.
50 Yards to 100 yards.
The process is the same at 50 yards. Fire three rounds at the target, making sure that the crosshairs are centered on the 10-ring. From the previous adjustment, you should see your rounds land fairly close to the mark. It’s unlikely, however, that you will be perfectly centered. So, you’ll need to measure again and then make the needed adjustments.
Repeat this process at 100 yards and then at 100-yard increments up to your desired zero range. One good part about firing at longer ranges is that the distance of error in your shots will become more pronounced. This makes it easier to measure and to adjust for that error. However, once you go past 100 yards, you will start to see holdover become a larger factor in your aiming, causing your shots to hit lower and lower on the target. At those ranges, windage will start to become a factor as well.
While you can’t exactly zero in horizontally at longer ranges because of variable wind speeds, you can zero in by compensating for holdover.
What is Holdover?
Essentially, holdover is the distance that a round drops as it travels to the target. Depending on your cartridge, exit muzzle velocity, and weight of the bullet, holdover will differ. This is why it’s essential that you zero with the same rounds that you’ll be hunting with.
As the range to the target increases, the bullet is going to drop due to the force of gravity. For example, given a 270 zeroed in at 100 yards, if you shoot at a target that’s 200 yards away, the bullet will drop 3 inches. At 500 yards, the bullet can drop almost 51 inches with a flight time of 640 milliseconds.
So at longer ranges, you aim higher, rather than using the elevation turret to adjust for that drop. If your scope has a Christmas Tree or mildot reticle, you can aim higher using those markings. There are also scopes with ballistic reticles where the distance is preset, making firing those distances even easier.
Longer Distance Sighting
Depending on the type of shooting you’re going to be doing, you can either use the above method to sight in your rifle at any range up to the maximum range for the round. However, if you’re going to be hunting, you can use another method, MPBR.
Maximum Point Blank Range (MPBR)
One of the easiest ways to sight in a rifle that is going to be used exclusively for long-range hunting (not range shooting) is to sight for Maximum Point Blank Range (MPBR). Essentially, MPBR is a way to sight your scope that takes into consideration not only the range but also the size of the target zone.
For example, an elk buck can have a 10-inch kill zone. That means that your bullet should hit anywhere in that 10-inch circle whether you’re at 50 yards or 350 yards.
So when sighting for MPBR, you're essentially calibrating your rifle to fire upwards at an angle. That means that at the bullet's height, it will be at 5-inches above the center-line. At the maximum MPBR range, it would hit the target at 5-inches below center-line. This calculation is dependent on the type of ammunition being used as well as the rifle firing the round.
There are several ballistic charts that will help you calculate what range to zero in on and what the maximum MPBR range will be. For example, given a deer with a 6-inch kill zone, and using a 7mm Remington Magnum, you should zero in at 254 yards. This will give you an MPBR of 300 yards. This means you can put the crosshairs on the vitals of a deer at any range from 0 to 300 yards and know that you’ll still hit inside of that 6-inch circle.
Whether you’re range shooting or going after trophy game at long ranges, it’s essential that you can place rounds inside a specified area. While the need is obvious for long-range target shooting, it's also advantageous for hunters. By sighting in your scope at longer ranges, you can take advantage of ballistic trajectory to ensure your shot placement in a set kill-zone area. An afternoon at the range or the quarry can be the difference between using your tags and coming home empty.
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