Shooting accuracy: How to zero a rifle scope

Whether you are going hunting or planning a casual plinking at the range, you want to hit the target you are aiming at, so the basic rule is to make sure your rifle is properly zeroed. Widely known quote “Only accurate rifles are interesting,” from famed hunter Col. Townsend Whelen is very applicable in our case. Knowing how to zero a handgun or rifle scope is an essential part of precision shooting and a core task for every rifleman that must be mastered. Zeroing is the process by which we create repeatable scope setting to produce as close an impact to the center of the crosshairs as possible at a known range.

It does not matter whether you are changing the scope or buying a new rifle it is important to know how to adjust the scope parallax on your rifle, so the projectile hits where you go for a specific distance. The process of zeroing your weapon system is rather straightforward but can be quite frustrating if you do not comply with any part of the process. The main parts of the zeroing process features of mounting, bore-sighting and hot verification on the range. Each of them is crucial for further advancing in zeroing.

Scope mounting

It is incredibly critical that your scope is adequately mounted;otherwise, it can be impossible to zero. The most critical things to ensure are that all mounted scope rings, rail and base have correctly tightened screws.

Sometimes you will need to use substances like Loctite to ensure when shoot a rifle the scope mount and the ring should not be loose from recoil.

scope mounting

The scope should have correct eye relief to eliminate scope shadow and subsequent parallax issues.  The riflescope should be at position to ensure an adequately levelled reticle, meaning the vertical crosshair lines must be entirely up and down in front of your eye.



Boresighting as its name says it means trying to achieve rough alignment of your barrel and scope by boresighting. 

A boresighting technique is quite simple with bolt-action rifles, single-shots and AR-15 platform guns, as you need only to remove the bolt or separate AR-15 into two halves and use the upper receiver without the BCG.

For other rifle’s constructions, you will need to use bore sighting tools involving collimators or lasers and rods placed down the barrel of the gun.

First, to eliminate the human error out of zeroing the scope make sure the rifle is in a stable position, as the stabilization is the most crucial factor. This could be arranged almost at any shooting range, to secure a rifle, you can use a gun vise or a bench rest with a sled.

Depending on your experience and weapon type you can put the target at 50 yards, but generally speaking, it is better to start at 25 yards as that initial short-range offer clean target and you’ll usually save some ammo.

Once you centered the target in the bore, now you should look through the optic and find the objective. Without touching the rifle, you have to align the scope reticle to be as close as possible on target. 

This adjustment you can do using the windage and elevation knobs until you see the same “picture” as through your barrel.

One thing that is often overlooked is the type of load you will use the zeroing process. The specific type of ammunition you plan to hunt with should also be used for the sighting in the rifle. It is important, since the bullets of different weights may have a different point of impact, resulting in misplaced shots.

At the range

Now we can start with a hot and more existing part of zeroing, shooting. Boresighting is not a perfect science so we cannot expect initial bull’s eye hits. After all, zeroing has nothing to do with how well you can shoot; it’s all about the weapon system, rifle and scope.

After three shoot group check the target and adjust your sights and do it again until you have reached your desired zero. While a zero at 25 yards should be about an inch low to get a perfect zero at 100 yards, at 50 yards you can make the same point of aim and point of impact.

The next step is moving your target at 100 yards, shooting three rounds group and making fine-tuning adjustments. A 100 yards range is ideal because it minimizes adverse weather conditions and removes as much human error as possible.

For short-range hunting situations, you may well want a clean 100-yard zero, but hunters are often setting a zero close to their expected engagement range.

It means that you might have to make adjustments, so the rifle shoots a bit high. Whereas some shooters advocate the thesis about keeping zero three inches high at 100 yards that will reach 300 yards with one inch of the drop, the others remain supporters of the old-fashioned theory of Jack O’Connor that 2 to 2.5 inches high at 100 yards would be just fine for most common calibers.

For shooting at longer distances, you’re probably going to set your zero out to 200 or even 600 or 1,000 yards. It means that you have to make a few fewer clicks to adjust for minor variances in the field. 

If you have a scope with a turret zero setting feature, it makes sense to set your turrets to zero at those ranges particularly if you are competition shooter with a dedicated rifle or long range hunter who used the large magnum calibers for extreme long range ethical harvest.

Unlike other shooters, tactical or competition, hunters are often limited with the ability of ethical shoot, because a wounded animal that will never be discovered and that will die in agony is not a perfect end of a day for the real hunter.

Tips and wrapping up

The good idea is to clean your rifle after no more than 20 shots in order to get the most accuracy from your weapon when zeroing. Wait until the barrel become cool completely and then recheck shots to ensure that you’ve maintained your zero.

If you master using turret adjustments to make your POI and POA converge, you should be able to find and confirm your zero at any distance with a minimal amount of expended ammunition.

Whether you purchase new rifle or scope or your equipment is roughly handled in transit, itis essential to zeroing a scope on a rifleand most hunters and competition shooters choose to re-confirm their zero before starting their hunt or match.