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View Full Version : POI POA shift @ 25 yards on a 50 yard zero.



AGENT TIKKI
10-12-11, 13:44
Need some help figuring out, what the POI/POA difference would be for at 25 yards for a 50 yard zero. I have both a 14.5" and 16" Ar15, and will be using M183 ball.

Can anyone point me in the right direction? Perhaps a resource I can used and refer to in the future if I decide to use other types of ammo? Like M855 etc etc.

Basically, I have a local 25 yard range, that I'd like to use to try and use to do a 50 yard zero, before going to a 200+ yard range that is a couple hours away from me. Any help would be greatly appreciated.

Failure2Stop
10-12-11, 14:04
Approx 1.5 inches low (POI below POA).
Will get you close enough to be on paper at 50.

There are targets that show you exactly where to hold POA and where to adjust POI at 25 for a 50 zero.

Here's one thread on it with targets available for download:
https://www.m4carbine.net/showthread.php?t=75940
Or you can just download it from here:
http://home.comcast.net/~j_colt123/25%20Yard%20Zero.pdf
Doesn't take a rocket surgeon to figure out what needs to happen once you look at it.

AGENT TIKKI
10-12-11, 14:28
Dude, thank you. Why didn't that show up on any of my searches.

Seriously, this solves everything.

You the man! :thank_you2:

markm
10-12-11, 14:37
Definitely confirm that when you get to a decent range. A 25m Zero is pretty crude and leaves a lot of room for error.

J8127
10-12-11, 14:46
Has anyone done this (try to get a 50 yard zero at 25) that can share how close it ended up being?

The only place I can shoot my rifle without paying dues and being subjected to asinine rules is out in the woods.

Failure2Stop
10-12-11, 14:53
Has anyone done this (try to get a 50 yard zero at 25) that can share how close it ended up being?

The only place I can shoot my rifle without paying dues and being subjected to asinine rules is out in the woods.

It's pretty variable, but it will get you close enough to at least be on paper. I use 100 meter zeroes and I skip straight from 25 (POI ~2" low) to 100 on initial zero and am usually within 2 to 3 inches at the 100. I rarely shoot more than 6 rounds at the 25. It doesn't need to be gnat's ass at close range, just close enough to hit paper at your actual zeroing distance.

We used to do a 36 yard expedient zero followed by 200 or 300 yard zeroing, and while it always required some adjustment at those ranges, it was always (as long as the shooter was doing their job) close enough to quickly establish zero. Due to change of sighting system we went to a 10 meter expedient, followed by a 100 meter zero, folowed by a 300 meter confirmation, with the same results. Never (or very rarely) right on with the first group, but close enough to establish groups and adjustments.

AGENT TIKKI
10-12-11, 14:59
Definitely confirm that when you get to a decent range. A 25m Zero is pretty crude and leaves a lot of room for error.

For sure, I really just hate wasting time and rounds trying to get onto paper while waiting 30 mins intervals to change out targets at the bigger out door range.

ASH556
10-12-11, 15:32
Has anyone done this (try to get a 50 yard zero at 25) that can share how close it ended up being?

The only place I can shoot my rifle without paying dues and being subjected to asinine rules is out in the woods.

I'm sure there are several variables (barrel length, load pressure and corresponding velocity, sight radius, etc).

However, I used the 25M zero notch on the elevation drum of my KAC 600M to zero at 25 yds. I then when and shot a Vickers Tactical class at 50 yds and was in the center black with my drum set at 200M. YMMV.

az doug
10-13-11, 16:25
I zero rifles for 100 yds by first sighting in for the offset poi at 25 yds. I use a ballistics app to determine what that offset poi will be for each cartridge/height of sight over the bore...

I always verify at 100 and it is very close.