The 36-yard zero is the "one hold to 300" setup: zero close, and for many 5.56 carbine loads the bullet crosses your line of sight a second time somewhere around 300 yards. It buys reach with a single aim point — and pays for it with a mid-range hump you need to know about.
An AR-pattern carbine carries its optic roughly 2.5 inches above the bore. The bullet starts that far below your line of sight and climbs through it at a shallow angle. Pick the zero distance and you pick the angle — and the angle decides where the bullet comes back down through the line of sight the second time.
Zero at 36 yards and, for many 55–62-grain loads at carbine velocities, that second crossing lands in the neighborhood of 300 yards. That near/far pairing is the whole idea, and it traces back to military battlesight zeroing, where a short confirmation distance was used to stand in for a 300-meter zero. The short distance is a proxy; the far crossing is the point.
The practical read: on torso-sized targets, a center hold works from the muzzle to roughly 300. On small targets in the middle — a 4-inch plate at 175 — you have to hold low, which surprises people the first time. The rise is the cost of the reach.
A 50-yard zero pairs with a far crossing around 200 yards for many of the same loads. Its mid-range rise is much smaller — roughly 1.5 to 2 inches — so it's flatter and more forgiving everywhere most people actually shoot. The bill comes farther out: with a 50-yard zero you can be half a foot or more low by 300.
These numbers are load-dependent — a 62-grain load from an 11.5-inch gun does not fly like a 55-grain load from a 16-inch. The Zero Considerations solver models both zeros for your exact load, velocity, and sight height, so you can see your own trajectory before you commit.
Yes. It's driven by height over bore, and a dot on a standard AR mount sits at about the same height as other optics. The far crossing still depends on your load and velocity.
Yes. Shorter barrels mean lower velocity, which pulls the far crossing closer. The app computes the actual crossing for your setup instead of a rule of thumb.
High — commonly a few inches for carbine loads. If you mostly shoot at 100, that's a point in the 50-yard zero's favor.
Zero Considerations — photograph the target, get the measured group and the exact clicks to dial, then keep the DOPE. One-time $9.99 on both stores — no subscription, no account, works with no signal.
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