quote:

Originally posted by DaBigBR:

quote:

Originally posted by cas:
Not a smart ass answer but.. sight it in for the distance you think you're most likely to shoot it. Then learn where it shoots at the less likely distances. (and write it down)

Well, assuming that the "most likely distance" is 10 yards and in, I'd say that zeroing for that distance is a terrible plan.

The trajectory of 5.56 at varying zero distances is very well established.

Go with the data.

DaBigBR is correct. Zeroing for something like 10 yards or 25 yards because that's the range you normally shoot, or because you plan to use it primarily for shorter range defense, is a Bad Plan.

As explained (and shown) a 50 or 100 yard zero will be within a couple inches of POA out to several hundred yards. Basically out to the maximum range that a typical person would be shooting a rifle with an unmagnified red dot optic. You don't have to think about it; put the aiming point on the target and pull the trigger.

Whereas a 10 yard or 25 yard zero will be hitting one or more feet high at anything past close range.

For example, a 16" AR15 with a 62 grain 5.56 round that has been zeroed at 10 yards will be (roughly) +10 inches at 50 yards, +15 inches at 75 yards (over a foot high), +20 inches at 100 yards, +24 inches at 125 yards (2 feet high), +30 inches at 150 yards, and +37 inches high at 200 yards (over 3 feet high). It will eventually crest at +56 inches (4.6 feet high) at ~450 yards.

There's no point in zeroing at short range because that's where you normally shoot, and then having to try to guesstimate and aim low by several feet when you go to attempt to shoot it at 50 yards or more, when you can just zero it for 50/100 instead and be good to go at any reasonable distance.

Right.
The idea is to sight in where you will be able to predict the "range" of rise and drop from specific distances. Then you can shoot at 10, 25, 40, etc and make not of the point of impact.

I used a 50 or 75 yard zero for 3 gun. The range I shot at most often was limited to 100 yard shots, so that worked well, but it is workable out to 200 yards. I can't see will enough with an unmagnified sight to shoot at man sized targets past 200 yards. For those shots, I would need a magnifying sight.

I also use a 50 yard zero but I will confirm and fine tune it on a 200 yard target. There is often a slight error in your 50 yard zero that will be lost amidst the dispersion of the bullets, which will reveal itself if you fine tune at 200 yards.


I have lost count of the number of first time 3 gunners who show up with a LPVO that they zeroed at 50, counting on the 200 yard zero to be good. They get eaten alive on the 300+ yard targets because they didn't confirm their zero at longer ranges.