I was an early adopter of optical sights for rifles and competition, but a relatively late adopter of an optic on my everyday carry. My overall concern with optics on an everyday carry mainly centered around mechanical reliability and the user’s skill. Was the dot there every time it was needed? Could you present to the dot every time?
Modern higher quality red dots have become very reliable and as battery life has gone up can be left on year-round. Learning to shoot using an optic and presenting to the dot are easily addressed by training. However, that leaves one additional issue and that is the need to zero the dot. Though this can be done by others (any many people do) I feel if it is your defensive firearm the process of zeroing should be done by you for you.
What is Zeroing? Realistic Considerations
Zeroing refers to the adjustments that need to be made to ensure the point of aim (in this case, the red dot) is aligned with the point of impact (where the bullet hits). Though the actual distance the sight is zeroed for is not an issue for most defensive distances with a handgun (0-25 yards), the process of zeroing is complicated by a few factors.
- The path of the bullet is not a perfect straight line. Bullets tend to follow parabolic arcs effectively dropping below the alignment of the barrel the further the bullet travels. This means at longer range the bullet itself will pass below the point of aim due to gravity.
- Red dot optics tend to sit higher on the firearm than traditional sights. This means that the point of aim (the dot) and the point of impact (bullet hitting the target) are following two different paths.
- The shooters’ own skills will make finding zero easier or harder. Finally, the distance which the shooter decides to zero (point of aim and impact meet) will vary from person to person based on potential use and skill.
Placed together, these factors will help determine what distance to zero your handgun optic. Although there are many suggestions of distances to zero various handguns and rifles, I suggest a very pragmatic approach based on the last two factors in zeroing a handgun. To accurately zero your handgun you need to realistically be able to place three to five rounds into a consistent grouping. Though smaller groups are better, consistency is likely most important.
It is easier to zero if you can consistently place three rounds into a one-inch or smaller group, but if your groups are larger but consistently within a certain area or grouping (two-inch or three-inch for example) then you can still extrapolate a center point for each group. If larger groupings are more representative of your shooting, I would encourage using five-round groups to better estimate your center point (estimated point of impact). This leads to the first determinant of what range you zero your handgun at: What is the range you can consistently shoot reliable groups at? The second factor is what ranges do you think most defensive encounters are likely to occur?
I have often seen people zeroing their subcompact handguns at 25 yards. Even if they are capable of getting reliable groups at that distance, what is the likelihood of needing to shoot at that distance, with that gun, in a defensive situation? Thus, after honestly assessing what ranges you can shoot consistent groups, I would next suggest sticking to a defensively likely distance (15-30 feet) for zeroing a handgun intended for personal defense.
My handguns are zeroed at 30 feet. I can consistently get three-round groups into a one-inch area at that range, and it is a good defensive distance. The differences between point of aim and point of impact at closer ranges will be off, but by no more than the distance between the dot and the center of the barrel (on most handguns less than one inch) with the point of impact being slightly lower than the point of aim. Past 30 feet the point of impact will be slightly above the point of aim, but again this shift will be less than one inch at any distance that I can reasonably be accurate at with a handgun. The end result is that if zeroed at 30 feet I do not need to adjust my aim, I just know that the point of impact will vary by about one inch either up or down compared to my point of aim (which is still very accurate for defensive purposes).
Once you are sure your optic is securely fastened (I suggest Loctite) to your firearm, the first step is deciding and testing your groups and deciding at what distance you want to zero. The goal here is not to connect your point of aim and point of impact, it is to see if you can get a consistent group of three to five rounds at the distance you have chosen. Zeroing is all about accuracy and you should do as much as possible to guarantee a consistent group.
I often use shooting sandbags or a rifle rest and a table to help brace the firearm to reduce variance in my shots. I would also suggest using grid targets with either ½-inch or one-inch squares to help adjust each group. Many options are available for free online. Every shot should be fired with the point of aim (the dot) directly over the middle (bullseye) of the target as we need to quantify the distance between the point of impact (bullet holes) and the point of aim (bullseye center of the target).
Once you have confirmed your group and distance for zeroing purposes it is time to start adjusting. Your red dot’s owner’s manual will include information on this, but most red dot optics will have two small dials. One will be elevation (height) and the other windage (left to right). Most optics will also indicate which direction (clockwise or counterclockwise) you need to turn the dial in order to adjust the point of aim to match the point of impact either higher or lower, or left or right. If this is not clear on your optic consult your user’s manual.
These dials are generally factory set that each small movement (click) equals 1 MOA. MOA stands for moment of angle, but the important part is that it represents one inch of movement at 100 yards. Thus, at 100 yards one ‘click’ of adjustment equals one inch of movement in aligning the point of aim and point of impact. We are almost always going to be adjusting at much closer ranges such as 10 yards where one ‘click’ equals about 1/10 of an inch, or 25 yards where one ‘click’ equals ¼ of an inch.
My suggestion is to adjust the height first firing a new three to five-round group after each adjustment (make sure the gun is fully cleared between each firing as you make adjustments) until the point of aim and impact are on the same horizontal plane as the bullseye. Then adjust for windage left or right. As you adjust, write down each adjustment in clicks or quarter or half turns of the dial if you do not feel the ‘clicks’ as you adjust. If you find that an adjustment makes it worse, undo that adjustment. If your next group is back where you started, reverse the direction from then on to adjust.
I would love to say that every user manual and direction instruction on the optic are always accurate, but I have run into more than one optic that requires correction directly opposite of those suggested to get it zeroed properly. Once your point of aim and point of impact are consistently both on the bullseye your optic should be zeroed. Reconfirm this zero at least once and feel free to adjust further as needed.
Another option is dry zeroing. If you have a laser boresight you can likely get your zero closer to where you want it before ever firing a live round. This dry process involves triple-checking that the gun is unloaded and using the bore laser to adjust the dot (point of aim) to coincide with the laser (assumed point of impact) at the range you want to zero. This likely will still require some refinement through the live fire process listed above.
Checking and Re-zeroing
A reliable optic should not require re-zeroing as long as it is securely attached to the firearm. I would also recommend, once zeroed, marking the dials with a fine paint pen with a straight line starting on each of the two dials and continuing onto the body of the optic. This becomes a quick method of checking if the settings have shifted.
Assuming you have a quality optic secured with Loctite, there will likely be little need to re-adjust. However, it is always a solid idea, especially if this is your everyday carry, to confirm zero with three to five rounds at the zeroed range at the start of any practice session to ensure zero has been retained. If it has not, you can re-zero the optic, but if it is secure and you are still often losing zero this is likely an electronic problem that needs to be addressed by the factory.
Unlike traditional iron sights that are typically already zeroed from the factory, red-dot optics do require a systematic process to ensure their zero works for you. Just make sure you zero your optic using consistent groups. I have often witnessed new optics users insisting on zeroing their guns at far greater distances than they will likely ever shoot and that they cannot get any consistent groups from with which to adjust.
Optics are of great advantage. However, the zeroing process is very dependent on the shooter’s fundamentals and ability to shoot consistently. If you find trying to get a consistent group frustrating even using bracing bags, I would strongly encourage you to first work with an instructor on your shooting fundamentals and then work on zeroing your optic. Either way, I hope this article was helpful to you as an introduction to zeroing your handgun optic.