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Why Does My Scope Lose Zero? — How to Troubleshoot & Fix It

Why Does My Scope Lose Zero

Holy buckeyes!

Sometimes, you just have those frustrating moments when you think you’ve got a perfect shot, only for it to miss.

Or maybe, you just so happen to have problems sighting in your optics.

If this happens to you, it seems like your scoped rifle could have LOST ZERO.

What Does It Mean for My Scope to Lose Zero?

Before we go into HOW to fix a scope that has lost zero, let’s talk about what it means for a scope to hold zero.

To zero in a scope means to align the scope with the bullet trajectory. This would allow the bullets to hit the target at a distance.

Of course, there are a lot of factors that go into making sure your bullet hits its target. There’s chamber pressure, wind speed, distance, etc.

While you can’t specifically dictate a bullet to go exactly where a scope is pointing, it is possible to adjust the scope so that the crosshair will point at the exact spot you want your bullets to go.

This adjustment, if done properly, is what it means to make a scope hold zero.

If you fire a shot, and the bullet is FAR off its aim, you could say that the scope has LOST ZERO.

How could this have happened?

Let’s look at some reasons for this and how you can possibly troubleshoot it to ensure your scope will hold zero.

Why Does My Scope Lose Zero? — 7 Possible Causes

Now that we know what it means for a scope to lose zero, let’s look at some of its possible causes.

1. Defective Scope

The simplest reason for a rifle scope losing zero could simply be that it is a defective scope. There can be many reasons for this.

  • The rifle scope itself is of a low-quality make and model.
  • You are using an old scope that has degraded over time.
  • Abuse of the rifle scope (e.g., hitting or dropping it) has caused damage that affects its accuracy.

If you feel as though your rifle scope may be defective, it may be best to get a new one, preferably of good quality

If you feel your scope is NOT defective but you still experience issues, you might want to revisit sighting into rifle scopes properly.

2. Barrel Heat

This may be surprising, but the temperature of the barrel, especially for hunting rifles, actually plays a large role in the accuracy of the shot.

A barrel at ambient temperature, also known as a cold barrel, makes the most accurate shots. When a few bullets have already been shot, it is known as a hot barrel.

A hot barrel tends to shoot too high or too low.

This is because the change in temperature as the barrel heats up causes it to swell and change in stresses to alter shots. This causes it to shift a bit with every shot.

Additionally, a barrel can even fall off if it overheats.

This is especially an issue with rifles that have a thin barrel and a high volume cartridge. Thin barrels tend to heat up faster, while high volume cartridges tend to shoot hotter.

While rifles with this configuration make for a first shot with a deadly aim on a cold barrel, the heat from this combination of factors is disastrous for any ensuing shots.

The combination of these two factors makes for a DISASTER.

3. Dirty Barrel

Dirty barrels are quite normal on the field as some debris is leftover from each bullet that leaves the rifle.

However, a dirty barrel can also affect the accuracy of your shots.

Rust and debris inside the barrel can cause blockage and cause the shot to lose accuracy, even if the scopes are accurate.

Additionally, any corrosion or copper fouling inside the barrel may also cause a misfire or a failure of shooting.

With a dirty barrel, your shots may be missing even if you’re doing everything else right.

4. Wrong Ammunition

Some bullets may have variations and inconsistencies that may cause your rifle losing zero. For example, it may be misshapen or have an incompatible weight, causing it to shoot differently, even for just a single shot.

Some bullets may also be corroded or dirty, thus contributing to a change in direction and shot.

It is important to note, also, that different rifles are suited for different rounds. Using the wrong type of bullet may damage the shot and the rifle if it is not made to sustain such heavy recoil.

5. Mounting Problems

Faulty scope mounts or bad mounting can definitely contribute to the inaccuracy of scopes.

When the scope mount is not screwed properly, the rings may become loose with every shot. This inevitably throws off your hunting rifle’s ability to shoot properly.

On the other side of the coin, however, there is the issue of the screws being tightened in far too much. Screws that are too tight can cause problems with the screw holes and mount base.

There can also be the issue of the scope being mounted improperly. For instance, it could have been mounted upside down, with the windage turret on top and the elevation turret on the left side.

The scope mount could also have been attached slightly off-center on the gun due to operator error.

We don’t know about you, but we know we can’t read upside down, much less shoot.

6. Faulty Adjustments

The elevation and windage turrets on your scope may be improperly adjusted.

Elevation turrets control the movement of the reticle up or down, while the windage turrets control it from left to right.

If scopes aren’t adjusted properly, they may be pointing a bit too much to the left or right, or angled too low or high, for the right shot.

7. Parallax Issues

Parallax is an optical illusion wherein the reticle doesn’t point to the exact location of the target. It may cause an object to appear slightly to the left or right of its actual position, making you lose your shot.

Parallax issues are most prominent in scopes with higher magnification. To avoid parallax issues, look for a scope that can make an auto adjustment to make up for it.

You also need some practice to understand how to make the necessary adjustment to your aim needed to make up for the parallax.

How to Troubleshoot Your Rifle Scope

Now that we know some possible causes for your hunting rifle to lose accuracy, let’s look at some possible quick fixes.

1. Allow Your Barrel to Cool Down Between Shots

Hot barrels tend to give inaccurate shots. As such, you’ll want to have as close to a cold barrel as you can for your shots.

If you can, wait a minute or so before firing again. This will allow your gun to recover and shoot better shots.

2. Clean Your Rifle Regularly

You always want to be sure that the barrel of your rifle is clean of any rust, debris, or corrosion.

Make it a point to make regular checkups and clean your rifle regularly. Don’t walk into the field or range with a dirty barrel!

Once you are on the field, be sure to clean your barrel. It is recommended to clean the barrel with a powder and a copper solvent every 20-30 rounds. This will ensure a smooth shooting experience.

3. Buy the Right Type of Ammo for Your Rifle

Don’t just use any kind of bullet for your rifle. Be sure to check what type of bullet your rifle is made for.

Remember that rifles are not created equal, and there is a large range of ammo to choose from.

Once you know what sort of bullets your gun can and can’t take, you can experiment with different brands.

Don’t be afraid to shoot different kinds of ammo until you see what kind of bullet and brand your rifle likes. It’s best to check these at a shooting range and not out on the field so that you won’t be missing out on any hunting.

It’s also best to get bullets from the same lot to avoid inconsistencies.

4. Secure Your Mounting Properly

Be sure that all the screws in your mount, especially on the scope rings, are tightened properly.

It will cause problems if scopes and scope rings are screwed too tight or too loose. If you are having problems with the accuracy of your shots, you may want to check on the screws of your mounting.

Also, make sure that your scope is right side up to avoid any problems such as shifting the reticle left or right when you really meant to shift it up.

Make it a point to ALWAYS check on the security and condition of the rings and scope before actually shooting your gun.

5. Bore Sight Your Rifle

Boresighting helps zero the scope by aligning the barrel’s bore axis with the target.

While it can be done by a laser or mechanical bore-sighter, it is also possible just to eyeball it.

Eyeballing it might sound crude and difficult, but it is a great way to fix your aim without any additional expenses.

If you want to boresight your gun without any additional tools, put the gun in some sort of cradle that will stop it from moving. A weighted cardboard box notched on the two top edges makes for a great DIY cradle.

Once you’ve secured your rifle, you can move on to adjust your rifle:

  1. Remove the bolt.
  2. Look down the barrel and manually adjust it so that a bull’s eye is centered at about 30 yards.
  3. Adjust the turrets until the reticle is centered to the bull’s eye. Be careful not to move the rifle!
  4. Take a shot at a paper from about 10 yards.
  5. Taking note of where the hole appears, realign your rifle using the windage and elevation dials so that the crosshair is right above the first shot.

Once you’ve followed these easy steps, the barrel and scope should now be aligned to point at the same place.

It should be good for 30-200 yards, or even 250 yards if you really did it well.

6. Be Aware of Proper Click Adjustment

It is especially important to know how your scope moves and how you can calibrate your scope accordingly.

Different scopes work differently. Some scopes move at a 1/2 inch per click at 100 yards, while others scopes still move at 1/8 an inch per click. Most scopes move at 1/4 inch per click.

Let’s talk about proper click adjustment with regards to a 1/4 inch click since it is the most common out there.

If you want to shift your point-of-impact 1 inch at 100 yards, you’ll need to dial in four clicks.

Let’s say, then, that you fire your first shot and find that it is skewed 2 inches to the left. To remedy this, you’d have to dial in 8 clicks to the right.

However, if you fire and find that it is 4 inches too high, you’ll need to turn the elevation turret 16 clicks down.

After your first shot, take note of where your next shot lands. If it didn’t shoot as expected, there’s no need to panic.

However, don’t rush to readjust your clicks!

The erector tube, which adjusts the reticle position, sometimes doesn’t shift as expected with the dials. However, it does shift after being jarred by recoil.

To use this to your advantage, take two more shots to give the erector tube a chance to shift properly. If it does move properly, with just that one shot out of place, then the erector tube was probably just stuck.

TAKE NOTE: If you moved to adjust your clicks immediately after the second shot before recoil can make any adjustment to the reticle, you might end up with a double adjustment, which will just make things worse for you.

7. Rap the Cap

“Rapping the cap” is a way to minimize the possibility of the erector tube getting stuck while zeroing in. It is also great for clearing up a sticky point.

It may sound a bit intimidating, but it’s actually quite simple. There are two ways to do it:

Method 1:

After turning the adjustment clicks, tap the top of the turret several times. This can be done with a screwdriver handle and is meant to mimic the recoil that loosens up a stuck screw/tube junction.

Method 2:

  1. Memorize the current turret setting and turn the dial to make a complete rotation past that number.
  2. Make another rotation around the setting.
  3. Return to the previous setting.

The point of the second method is to cause added pressure that can clear a sticky point.

For best results, combine the two methods for better chances of success.

Conclusion

We’ve given above a few reasons for your rifle scope to possibly lose zero, as well as how you can fix this problem.

We hope our little tips and tricks helped you diagnose and troubleshoot any problems you have, not just with your hunting rifle, but with any of your guns!

However, if you’ve tried these and all else fails, it may be time to retire your scope and find yourself another scope that can give you the love you deserve.

PRO TIP: You can also practice with an iron sight to improve your aim.

Keep shooting and practicing to improve your aim. Happy shooting!

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