Troubleshooting Riflescopes

Note: Adjusting the riflescope to zero should not be attempted until a satisfactory 3-shot group has been achieved.

The most common issues with zeroing include:

• I'm running out of adjustment when zeroing.
• I dial my turrets, but nothing happens.
• I dial a lot and nothing happens, but then after one shot it suddenly jumps to another location (wandering zero).

These are caused by one of the following:

1. Over-tightened rings. We recommend 15-18in. pounds on most ring sets, but please feel free to call and ask if you have questions about your specific rings.
2. Adjustable rings and bases being used are not adjusted properly. If you have adjustable rings and have questions about installing them, feel free to call us. We are happy to walk you through the process.
3. A misalignment in the rifle’s barrel and action or receiver. If you do not have adjustable rings or bases and have to use up a lot of windage/elevation adjustment (or run out completely), you may have a rifle with a barrel/action or receiver that is out of alignment. This can sometimes be corrected with an adjustable ring or base set or a canted base. Please give us a call if you have questions on the process!
4. A misalignment of bases. This can cause the rings to tighten unevenly around the scope tube and cause impingement of the tube or slipping of the riflescope in the rings. When using 2-piece bases, we recommend checking alignment with alignment bars and lapping the rings into proper alignment if necessary.
5. The scope is sliding in the rings. Check to make sure it is secure.
6. The riflescope’s main tube is bent. This can happen with hard impact or other uneven force applied to the scope tube. Roll the scope in the bottom ring halves to see if it is bent. If bent, the scope will appear to lift out of the rings rather than staying flat and rotating in place. Please give us a call if this has happened.

1. Your leveling tools used to mount the scope, and the reticle inside your scope are properly aligned, but the way you are holding the rifle causes your eye to perceive the reticle as canted. For example, right-handed shooters shouldering a rifle commonly report a reticle appearing to be canted to the left, or counter-clockwise. Left-handed shooters will generally report seeing the reticle canted to the right or clockwise. To fix this, try positioning yourself completely behind the rifle (chin aligned with the buttstock) looking through the riflescope at the reticle straight-on. This tends to eliminate that illusion created by having your head turned slightly while shouldering the rifle.
2. Aiming at a target or background that is uneven, or shooting from uneven ground may cause a reticle to appear canted. Moving to more level ground may eliminate this canted appearance. A shooter not accustomed to shooting with a bubble level tool installed on their rifle may make the mistake of believing the reticle is canted because of the way the rifle needs to be held in order for the reticle to be level. You can verify this again by getting completely behind the rifle to confirm proper alignment.
3. Your bubble level is sitting on top of the turret cap. This can skew your results by making the riflescope turret appear to be sitting level in relation to the rifle when it is not actually sitting level. Sometimes, the turret cap (or the fiber optic indicator on the turret cap) will sit crooked and cause the bubble level to be canted slightly. Rather than using the top of the turret cap, try putting the level on the inner turret post top (or using feeler gauges on the bottom of the scope) to level the scope.
4. Your bubble level is not accurate. To test, place it on a table and note the location of the bubble. Spin the level 180 degrees and note the location of the bubble. If it is not in the same spot, your level is not level.
5. The reticle is actually canted. Although very rare, this is a possibility. You can check reticle cant by lining the reticle up with any straight line and dialing the turret up and down. If it follows the line, you are good to go. If you are still in doubt after reading and investigating some of the potential causes and would like to speak with a specialist, the Technical Support team would be happy to help

1. Shooting at a target too close. Verify your particular riflescope’s parallax focusing capability. For example, a riflescope with fixed 100-yard parallax or 50 to infinity parallax may have some distortion when shooting at 10 or 25 yards, because the target is too close for the rifle’s focusing capability.
2. Mirage is a heatwave-like distortion that may cause significant distortion on targets at a long distance. It can occur in a variety of different temperature patterns but will be most noticed when shooting at extended distances with a high-magnification riflescope. Sometimes backing off the magnification can help alleviate this issue.
3. Barrel or Suppressor Mirage. This effect is similar to mirage observed downrange but originates from the barrel or suppressor getting hot after several rounds have been fired. The shooter can alleviate this by letting the rifle cool or installing an anti-mirage suppressor shield/ barrel mirage band.

Check to ensure you are thinking in terms of moving the bullet’s point of impact rather than your actual point of aim when you dial your turrets. For example, when you are shooting low and dial your elevation turret ‘up’, your reticle should actually physically move downward, but it does this so that you need to point the barrel ‘up’ in order to get back on target again. When you move your barrel up, it brings your point of impact up and on target where you want to hit. This can be confusing when initially bore sighting the riflescope as this is the only time where you want to think about actually moving the reticle, but once you start shooting and thinking of moving the bullet holes down range rather than moving the reticle, it will be much easier.

The specifications chart for any riflescope will list the scope’s total range of adjustment for both elevation and windage. It’s important to consider that this is the total range of adjustment available from the absolute bottom to absolute top, or most left to most right of the scope. When you receive your scope new from the factory, it will be optically centered in the middle. Though unlikely, assuming your zero is at that optical center, this would mean you have exactly half the total range of adjustment in all directions. If you’re shooting long range and dialing ‘up’ as you extend your range, you will have half the total range of adjustment to account for bullet drop.

To put this into perspective, The Diamondback Tactical SFP 4-12x40 has 70 MOA of total elevation adjustment. Again, assuming we’re zeroed at the optical center, we’ll have 35 MOA of available adjustment to account for bullet drop at longer distances. If you need more available room for adjustment than your riflescope provides, consider getting a canted mount or base. 20 MOA canted mounts and bases are quite common and ‘cheat’ in some extra adjustment to your scope by canting it down slightly, causing you to zero higher in the scope’s range of adjustment, leaving more room for adjustment below to dial out to greater distance.