Written by my friend Christopher Bean. Italicized text throughout this article is all mine.
Christopher Bean originally posted this to his FB page and after some light editing I am sharing this here with his full permission. I took on the work of editing and sharing this here for the love of the game.
If you’re reading this, it’s likely because you’re serious about modern handgun shooting.
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We all know that the Internet was primarily created to share images of cats. Also, the Internet exists for the express purpose of arguing about arcane and esoteric topics as they pertain to shooting. Handgun red-dot zeroing is definitely one of those subjects.
Does It Really Matter That Much?
With the recent upsurge in advocating for longer-distance defensive shots with pistols and the current news stories of heroic citizen interventions against mass-shooters, readers can prepare for Internet influencers and instructors to pontificate on “ideal” distances for handgun red-dot zeroes.
Whether it’s 10, 15, or 25 yards, zero distance choice often seems like a culty dogmatic decision instead of a more rational mathematical one.
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In reality, the ballistics of modern handgun ammunition in the context of practical engagement ranges render the actual mathematical differences between zero distances marginal. For clarity’s sake, let’s call practical pistol engagement to sit between 0 to 50 yards.
Defining A Pistol’s Red-Dot Zero
A “zero”, whether from a handgun or rifle, is simply a reference point along a curve of travel.
The efficacy of choosing a zero distance ultimately depends entirely on the shooter’s working knowledge of their firearms offset and point-of-impact (POI) behavior across distances.
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Rifle or pistol, the line of sight is parallel to the bore. At the same time, a firearm’s barrel is aligned to coincide with that line of sight. This results in the bullet’s arc-shaped flight path “intersecting” the dot’s reticle twice, once on the way up (the near zero) and once on the way down (the far zero).
In terms of the modern handgun with a mounted red-dot sight, the optic sits roughly 0.9 to 1.2 inches above the center of the bore. The big variable here depends on individual optics plates and slide mounts.
For example, consider a 9mm 124-grain projectile with a muzzle velocity of approximately 1,150 feet per second. This pistol load is as standard as they come.
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Fired from nearly any semi-automatic pistol, the physical variation of this 124-grain bullet’s trajectory between common zero distances would remain relatively tight across all those “practical engagement distances.” The rub is actually knowing the math and not arbitrarily selecting the intersect as the zero adjustment.
Comparing 10, 15 And 25-Yard Zeroes
At distances between 3 and 7 yards, these three zero adjustments would print lower, with an impact of roughly 0.3 to 0.9 inches. This is due to mechanical and physical height over bore offset that manifests at very close ranges. Move to the 15 yard line and a 10-yard zero would impact about 0.4 inches high. A 15-yard zero would obviously be dead-on, and a 25-yard zero would impact roughly 0.3 inches low.
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At 25 yards, that 10-yard zero’s ballistic trajectory peaks at a maximum height of 0.6 inches. Our 15-yard zero would impact just 0.1 inch high. Naturally, the 25-yard zero would be dead-on.
Even doubling the distance to 50 yards, the delta between a 10-yard zero (0.8 inches low) and a 25-yard zero (2.3 inches low) is practically about 1 ½ inches.
This reality highlights why a shooter’s hold map supersedes the specific zero distance they initially chose.
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It’s crazy to think about the fact that we’re discussing differences in points of impact between 1 and 1 ½ inches. These are tiny measurements in considering everything else pertaining to handgun shooting. In fact, think about how even proficient shooters would likely struggle to consistently shoot a “100” on a standard NRA B-8 target with a typical red-dot equipped pistol. And the 10-ring on a B-8 is 3.36 inches in diameter!
Understanding Mechanical Offset
As previously mentioned, every handgun red dot setup strikes low relative to point of aim between 0 to 7 yards. Again, a 10-yard zero and a 25-yard zero differ by less than a ¼ inch at 5 yards. This is why precision pistol shots, such as the “credit card A-zone” or those pesky 1-inch square targets, demand an intentional hold over regardless of which zero distance the shooter originally. calibrated initially.
(Key word being calibrated).
Between 10 and 30 yards, the maximum trajectory deviation across 10-yard, 15-yard, and 25-yard zeros stays well within an inch. In practical terms, this means that standard acceptable hit areas on targets like 8-inch circles or USPSA A-zones (6×11-inches), all point of impact differences between zero adjustments are functionally negligible compared to natural human induced shooting error.
Predictable Downrange Drop
Beyond 35 yards, all standard pistol caliber projectiles drop fairly quickly. Therefore, knowing that a 25 yard zero requires holding slightly high at 50 yards is functional marksmanship, not justification of a zero adjustment choice. Arguing whether that drop is 1.7 inches or 2.3 inches matters far less than actually confirming where the bullet impacts at that distance with a chosen defensive or practice load.
Zeroing at a distance simply provides a known stable reference during POI testing to ease the experimentation process of discovering and filing hold data. Once established, shifting focus from debating zero distance to mastering offsets at 3 yards and trajectory holds at extended ranges is what drives true performance.
Act accordingly.
No Red-Dots, No Problem
Lastly, for the “muh irons” crew…
Do you even know the distance that your iron sights are mechanically zeroed to?
Most don’t. Why?
Rarely do manufacturers include this data in their manuals. If you’re lucky they may discuss “holds” or provide a diagram of how they recommend you sight picture and alignment. But there isn’t much information out there.
The good news is that there’s virtually no difference between how iron sights or red-dot sights work. Both styles of aiming systems reference known sizes and bank on known or approximate trajectory intersections and are fixed in space.
Our job as practitioners is to know what the variances are on the path of travel.
Act accordingly.
In other words, Christopher is telling you to find out where your iron sights print with your carry or competition load. For example, I still carry my stock Gen5 Glock 45 that shipped with .200-inch tall Ameriglo Bold sights from the factory. My magazine is loaded with Speer Gold-Dot 124-grain JHPs, which is a no-brainer when it comes to defensive pistol loads. I’ve shot that Glock so much that I know for a fact that a center-hold at 5-yards with 124-grain Speer Gold Dot punches dead-on. Likewise, that same center-hold at 25 yards with that cartridge also has me dead-on at that distance. So yes, do what the man said and get out there and find out the relationship between your pistol, the target and your chosen load.
In The End
Who cares what “source” told you what the best zero was?
Focus on understanding where your holds print at different plots along the way. Know them inside and out. Test, retest and catalog them with all of your ammo. (Not unlike precision shooters or tactical snipers).
A sighting system is a sighting system regardless of whether its constructed of metallic posts or coated glass with LED arrays. Iron sights, red-dots, scopes, prisms: all are bound by mathematics.
Do this with reasonable frequency and those long shots you think are impossible become simple equations with only one correct answer.
Talk less, shoot more 😉
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