The improved battlesight zero: one close-range confirmation, center holds out to midrange.
The 36 yard zero was popularized by the USMC as an improved battlesight zero: sight in once at 36 yards and the bullet's arc stays close enough to your line of sight that a center hold works from room distance out past 200 yards without thinking about holdover.
Compared to the older 25 yard zero, the 36 pushes the near crossing further out, which flattens the midrange hump considerably — the bullet peaks around three inches high instead of seven. For a defensive or general-purpose carbine with a red dot, that difference is the whole argument.
One honesty note: the "36/300" pairing you'll see quoted everywhere assumes a 20-inch barrel pushing M855 at rifle velocities. From a 16-inch carbine shooting 55gr at ~2,900 fps, the far crossing lands meaningfully shorter — the table below shows what this load actually does. Confirm on steel at distance rather than trusting the slogan.
Bullet path relative to line of sight, 5.56 NATO / .223 Rem, 55gr at 2900 fps, 36 yard zero, standard atmosphere. Plus is above your aim point.
| DISTANCE | BULLET PATH | HOLD (MOA) |
|---|---|---|
| 25 yds | −0.7″ | 2.8 UP |
| 36 yds | 0″ | — zero |
| 50 yds | +0.8″ | 1.6 DOWN |
| 100 yds | +2.9″ | 2.7 DOWN |
| 150 yds | +3.0″ | 1.9 DOWN |
| 200 yds | +0.5″ | 0.2 DOWN |
| 250 yds | −5.7″ | 2.2 UP |
| 300 yds | −16.9″ | 5.4 UP |
Inside 15 yards your muzzle sits 2.6 inches below your dot — mechanical offset, not zero error. Hold high on small close targets. And your true far crossing depends on barrel length and ammo, so verify at distance when you can.
Yes, with one caveat: at across-the-room distance the bullet strikes roughly 2 to 2.5 inches below your point of aim because the optic sits 2.6 inches above the bore. That is height-over-bore offset, and it exists with every zero — the 36 yard zero just minimizes how long it lasts. Practice your close-range holdover.
It is the middle path. A 25 yard zero sends the bullet several inches high at midrange; a 50 yard zero is flatter still but needs a 50 yard lane to confirm. The 36 yard zero keeps the whole arc within about ±3 inches while being confirmable on ranges shorter than 50 yards.
The printed sheet is computed for 55gr at 2,900 fps. A 62gr load from the same barrel shoots close enough that your 36 yard group placement barely moves, but the far crossing shifts. For an exact target matched to your ammo, use the Customize This Target button above — the generator takes any bullet weight, velocity and BC.