The Firing Line Forums

Go Back   The Firing Line Forums > The North Corral > Lock and Load: Live Fire Exercises

Reply
 
Thread Tools Search this Thread
Old June 24, 2021, 11:59 AM   #1
napg19
Senior Member
 
Join Date: December 5, 2009
Location: Arkansas
Posts: 429
Sight in AR15

I normally sight in my ar15 at 50-200yds. This new rifle I'm thinking of sighting in at 25yds. Question is if I want to take a long range shot, say 100yds. My thought is to just aim 2 inches low at target and I should be close to bullseye. Am I right or wrong. Any help an all opinions appreciated. Thanks
napg19 is offline  
Old June 24, 2021, 12:33 PM   #2
hub1home
Senior Member
 
Join Date: November 15, 2014
Posts: 137
When I sighted in my AR, I only had a 25 yard range available. I wanted it sighted in for 100 yards so I sighted it at 2 inches high at 25. That gave me a 100 yard dead on.
hub1home is offline  
Old June 26, 2021, 09:34 PM   #3
HWS
Member
 
Join Date: July 1, 2018
Posts: 80
Why not just zero it at 100 yards? I think the 50-200 zero is the most practical anyway.
HWS is offline  
Old June 28, 2021, 04:36 PM   #4
Double K
Senior Member
 
Join Date: June 16, 2020
Location: Colorado
Posts: 486
Depends on if your using a scope or open sights, and if the sights are on a carry handle.
The higher your sights/scope are above the bore the LOWER your bullet will impact on the 25yd target if sighted in at 100yds. It's not unusual for a scope on an AR to be over 2" above the center of the bore, even a flat top with sights is slightly over 1.5" which would put a bullet over an inch low at 25yds when sighted in at 100yds. Typically a rifle sighted in at 25yds will also hit center of the target around 250yds with the top of the trajectory around 200yds, probably 3" high.
The trajectory of the 223 is relatively flat out to 200yds, the bullet is only shedding approximately 100fps per 100yds.
These are all estimates, informed however because I've hunted coyotes with an ar-15 since 1989 in the western plains.
Double K is offline  
Old June 28, 2021, 08:12 PM   #5
jmr40
Senior Member
 
Join Date: June 15, 2008
Location: Georgia
Posts: 10,439
The traditional way for military rifles with iron sights was to zero at 25 yards. That would also mean a 300 yard zero. But between 25 and 300 yards the bullet would be above line of sight. Several inches high, and enough to miss if you're shooting at a smaller target. But the original iron sights were designed to work with this method.

On my AR'sn with optics I just zero at 100 and go from there. That works better for me. And now that the military is using optics on all of their rifles I don't know how they are zeroing them.
__________________
"If you're still doing things the same way you were doing them 10 years ago, you're doing it wrong"

Winston Churchill
jmr40 is offline  
Old July 6, 2021, 09:08 AM   #6
baddarryl
Senior Member
 
Join Date: March 29, 2011
Location: Cape Fear!
Posts: 1,665
JMR is right. That is called Battle Sight Zero and was designed to be able to engage a man sized target without a sight adjustment to 300. What we do is set it up that way and then figure out drop and rise at 100, 200, 300 and record that and so on....if you have the range of course.
baddarryl is offline  
Old July 6, 2021, 01:08 PM   #7
MarkCO
Senior Member
 
Join Date: October 21, 1998
Location: Colorado, USA
Posts: 3,350
Quote:
Originally Posted by jmr40 View Post
The traditional way for military rifles with iron sights was to zero at 25 yards. That would also mean a 300 yard zero. But between 25 and 300 yards the bullet would be above line of sight. Several inches high, and enough to miss if you're shooting at a smaller target. But the original iron sights were designed to work with this method.

On my AR'sn with optics I just zero at 100 and go from there. That works better for me. And now that the military is using optics on all of their rifles I don't know how they are zeroing them.
This.

They have started to call it a 12" zero. The range at which the bullet will never be more than 6" high or 6" low from the aiming point. The new Army rifle qual is a bit harder and they have changed up a few things.

My son is at Basic as we speak. They shoot the qual course at least 5 times, first time with blanks. But they still have BUIS and they still have to zero and shoot with the BUIS once before they move on to the Optic, which they sight the same. He is doing BUIS zeroing today.
__________________
Good Shooting, MarkCO
www.CarbonArms.us
MarkCO is offline  
Old July 21, 2021, 01:29 PM   #8
jackstrawIII
Senior Member
 
Join Date: July 20, 2016
Location: Upstate NY.
Posts: 796
Hornady has a really good (free) ballistics program. Google it.

Just put in some basic specs (velocity, bc, etc) and you can know exactly where your bullet will be at every point along its journey.
__________________
In God we trust.
jackstrawIII is offline  
Old July 22, 2021, 04:46 AM   #9
armoredman
Senior Member
 
Join Date: May 22, 2007
Location: Arizona
Posts: 5,060
I zeroed my AR at 100 yards, simply because that was what I had been taught to do for decades. I think it will do.
armoredman is offline  
Old July 24, 2021, 06:30 PM   #10
Nathan
Senior Member
 
Join Date: July 1, 2001
Posts: 5,488
Try sighting in 0.5” low at 25 yds. That will have you battle zeroed to 350!
Nathan is offline  
Old July 24, 2021, 08:40 PM   #11
MarkCO
Senior Member
 
Join Date: October 21, 1998
Location: Colorado, USA
Posts: 3,350
Quote:
Originally Posted by Nathan View Post
Try sighting in 0.5” low at 25 yds. That will have you battle zeroed to 350!
Um, nope.
__________________
Good Shooting, MarkCO
www.CarbonArms.us
MarkCO is offline  
Old July 25, 2021, 10:58 AM   #12
Sharkbite
Senior Member
 
Join Date: November 4, 2013
Location: Western slope of Colorado
Posts: 3,579
I zero my 16” AR at 50. That puts me 1/2” low at 200 (im ok with that).

That zero allows the hold over lines in my Vortex Strike eagle 1-6 to line up ALMOST perfectly at 300, 400, 500 and 600. Again, not exactly, but close enough for field shooting.
Sharkbite is offline  
Old July 25, 2021, 01:49 PM   #13
Nathan
Senior Member
 
Join Date: July 1, 2001
Posts: 5,488


Pretty close….300…minus 0.25” would be better.
Nathan is offline  
Old August 4, 2021, 12:23 PM   #14
44 AMP
Staff
 
Join Date: March 11, 2006
Location: Upper US
Posts: 24,287
In 1975, we did not "zero" our M16A1s at 25m. We shot at 25m to zero the rifles for 250m. The target used was a special one, a few inches below the aiming point there was an "x" on the target, and that is where the bullet was supposed to hit.

We were told that sighting in this way would put us on target at 250m and still be able to get hits at 300m. They told us lots of stuff. Some of it was actually true...

We never shot our M16s at scored targets. Our qualification was done on an overgrown, badly in need of maint infantry range with the pop-up / knock down silhouette targets, many of which were in need of replacement as they had large (handsized) holes in them from being shot so much (COM). Actually hitting where you were supposed to sent your bullet through a hole in the target and did not knock the target down, and therefore was scored as a MISS!

The 25m pop up was small, just a "head and shoulders" silhouette, which we "snap shot" and I "missed" twice, before realizing I didn't miss, and I adjusted my aim to shoot the gravel in front of the target so a spray of rocks would hit it and knock it down.

I got most of the other range targets to fall by shooting them in the head. Shooting them COM almost always failed to knock them over because of the holes there.

I also found that, to reliably knock down the 300m silhouette, I had to aim 1/2 the target height above its head. Out of my entire company, only two people qualified shooting on the lane I had to use. I was one. And I was ticked off, because, I only qualified "Marksman" but I did qualify. None of the drill sgts managed that on that range lane, either. FT Leonard Wood 1975.

IF you're shooting a civilian rifle and something other than GI issue 55gr FMJ ammo, you might want to sight in a bit differently than we did back then with our 16A1s.
__________________
All else being equal (and it almost never is) bigger bullets tend to work better.
44 AMP is offline  
Reply

Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -5. The time now is 11:47 AM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2021, vBulletin Solutions, Inc.
This site and contents, including all posts, Copyright © 1998-2021 S.W.A.T. Magazine
Copyright Complaints: Please direct DMCA Takedown Notices to the registered agent: thefiringline.com
Page generated in 0.04562 seconds with 10 queries