What Distance Should you Zero your AR 15?

[Paladin]

A lengthy but thought provoking discussion about zeroing rifles:



My thought is that for home defense, the zero you chose (15 through 100 yards) won't make much difference. For distance rifles there are great reasons to use a 100 yard zero. But for your general purpose carbine this is an interesting approach to maximizing the utility of a zero.

[AF-Odin]

When I was active duty, we always zeroed on a reduced size target at 25 meters as POA/POI is coincident at 25 and 300 meters. In between 25 and 300, you may hit a bit high on a human sized target but should still hit. For close HD uses which will generally be less than 25 meters you will still hit COM or still make COM on a head shot. Maybe it is just habit, but I still zero at 25. In actual use, at ~50 meters which is about the distance I shoot most pigs, that zero seems to be pretty much where I aim, I hit.

[The Annoyed Man]

It has been my habit for a long time now to zero my iron sights and RDS optics at 50 yards, and magnified optics for whatever the optic manufacturer recommends, for the caliber of the rifle. For example, the Primary Arms 1-6x24 FFP SLX scope with their ACSS Raptor reticle recommends a100 yard zero for .223/5.56x45, and a 50 yard zero for .308/7.62x51.

A while back, I removed the ACOG and reinstalled the carry-handle rear sight on my A4 clone, and then tried the USMC armorer's modification to the rear sight drum (info here) that adds click values for 50 and 100 yards and allows a 50 yard zero. I have zeroed it at 50 yards, but haven’t yet confirmed the bullet rise/drop at one, two, three, four, five, and six hundred.

[Paladin]

Totally understand with the 25 meter zero.

I still zero most of my rifles at 25. Distance guns with scopes are set up at 100 yards. One rifle has a 50 yard zero because the reflex bullet drop compensator is designed to be zeroed at 50 yards.

But the video has me thinking that my EOTech and Red dot optics probably deserve another look.

[ORIGINAL TEX]

For civilian and home defense, where it woudl be rare or result in incarceration to engage a threat at 300 yards. I think it is best to zero an AR at 50 yards with the large aperture. If zeroed at 50 yards, then from about 10 yards to 200 yards the rounds should hit withing a 2-3 in vertical box, which should be good enough. If you need to engage anything beyond 200 you could flip to the small aperture which is supposed to be just a hair taller than the small aperture. At very close range (3-7 yards) point shoot or just bring the front post just above the aperture about 1mm. Works for me.

[Paladin]

Went out and gathered a fair amount of data.

For a 16 inch barrel and common loads it turns out that a 50 yard zero is ideal. It gives you a nice flat trajectory out to beyond 200 yards.

If you go with a shorter barrel, the ideal zero is a bit less (~30 yards depending on barrel length)

[C-dub]

Because of the ACOG I have on mine with the chevron and BDC I have mine zeroed at 100 yards. I've shot and 25 yards and closer distances for up close and personal knowledge if precision is required. At 25 yards aim with the 400 yard mark and for 10y or less on the 700 yard marker. Even if I forget or whatever and put the chevron tip center mass at up close and personal it is still only a couple inches off.