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-   -   Help Sighting in BUIS/optics (http://www.firearmstalk.com/forums/f20/help-sighting-buis-optics-79511/)

LaiePoi 12-27-2012 04:51 AM

Help Sighting in BUIS/optics
 
Hey guys just wanted to ask what is the proper way to sight in iron sights and red dots? I don't have any fancy equipment so just the general way would be just fine. Also, is there a certain distance that it should be sighted at? Probably not gonna shoot it beyond 100yrds as it is primarily a HD weapon and don't have magnification so just hoping for great accuracy inside that range. I have troy flip up battle sights and an aimpoint h1 if that matters. Thanks for any info you have

Jpyle 12-27-2012 05:14 AM

Quote:

Originally Posted by LaiePoi (Post 1067788)
Hey guys just wanted to ask what is the proper way to sight in iron sights and red dots? I don't have any fancy equipment so just the general way would be just fine. Also, is there a certain distance that it should be sighted at? Probably not gonna shoot it beyond 100yrds as it is primarily a HD weapon and don't have magnification so just hoping for great accuracy inside that range. I have troy flip up battle sights and an aimpoint h1 if that matters. Thanks for any info you have

There are dozens of sighting videos on Youtube, you can also get a laser bore sight which will get you "rough" sighted so you'll at least be on paper. Many choose to sight an AR at 50 yds...reason being is that the POI (point of impact) of the .223 round is almost the same at 50 and 200 yds due to the parabolic path of the bullet.

LaiePoi 12-27-2012 08:02 AM

Quote:

Originally Posted by Jpyle

There are dozens of sighting videos on Youtube, you can also get a laser bore sight which will get you "rough" sighted so you'll at least be on paper. Many choose to sight an AR at 50 yds...reason being is that the POI (point of impact) of the .223 round is almost the same at 50 and 200 yds due to the parabolic path of the bullet.

Thanks. I think I found a pretty good youtube video...just need to get the zeroing target now

Quentin 12-27-2012 03:05 PM

Google should turn up a PDF of the M4 25 meter zero target. It can be used for a longer zero with a little thought.

Sniper03 12-27-2012 03:20 PM

LaiePoi,

Jpyle and Quentin are on the money!
Here is a method I use.
1. Target at 25 yards to start. I shoot at the center of the target but the bullet should be hitting about 2 1/2 inches below center on the target at this point when close to a 100 yard Zero. I do this by taking a Bold Black Marker and putting a Cross on the target 2 1/2 inches below dead center on the target. When the impact is on the Black Cross I go to step #2, This is just to get it close when you move on out.
2. Move Target to 50 yards and tune it so the impact is in the center of the target
3. Move the Target back to 100 Yards for final adjustments.
I prefer a 100 yard Zero due to the fact most ballistics charts give various distance and bullet drop information based on 100 yards.
Then should you get an EOTech Holographic Sight or other sight just mount it on the rifle.
1. On the bench with good support dial the Reticle so that it rests on the top and in the middle of the front sight post.
2. Then finish Zeroing at 100 yards. By doing #1 it will be very close and at least on the paper. And you can fine tune at
that point!

03

LaiePoi 12-27-2012 06:26 PM

Thanks for all the great info guys! Don't know if I completely understand the bullet trajectory yet. So if I zeroed at let's say 100 yrds, then if I shoot anywhere closer like 25 yrds then I should expect it to hit low?

Is there some kind of chart that shows trajectory at different distances?

Sniper03 12-27-2012 06:35 PM

LaiePoi

You are exactly correct! When your rifle is sighted in and Zeroed at 100 yards your rounds should be hitting the target low at 25 and in. The reason for that is at close range the line of sight looking through the sights will be around 2 1/2 inches higher than were the line of bore is. (The actual barrel) As we say at close range the line of sight and the line of bore are at different levels. I will do some research and find a chart for you.

03

LaiePoi 12-27-2012 08:21 PM

Quote:

Originally Posted by Sniper03
LaiePoi

You are exactly correct! When your rifle is sighted in and Zeroed at 100 yards your rounds should be hitting the target low at 25 and in. The reason for that is at close range the line of sight looking through the sights will be around 2 1/2 inches higher than were the line of bore is. (The actual barrel) As we say at close range the line of sight and the line of bore are at different levels. I will do some research and find a chart for you.

03

Ahhh i think I'm beginning to see the light now! So since the bullet has an arc, then shooting beyond 100 yrds (where zero'd) would make the POI higher until the bullet starts to drop which I'm assuming would be somewhere beyond 300 yrds....correct?

Jpyle 12-27-2012 08:25 PM

Quote:

Originally Posted by LaiePoi (Post 1068420)
Ahhh i think I'm beginning to see the light now! So since the bullet has an arc, then shooting beyond 100 yrds (where zero'd) would make the POI higher until the bullet starts to drop which I'm assuming would be somewhere beyond 300 yrds....correct?

Exactly...

http://demigodllc.com/~zak/firearms/optics_1.png

Quentin 12-27-2012 08:34 PM

Quote:

Originally Posted by LaiePoi (Post 1068420)
Ahhh i think I'm beginning to see the light now! So since the bullet has an arc, then shooting beyond 100 yrds (where zero'd) would make the POI higher until the bullet starts to drop which I'm assuming would be somewhere beyond 300 yrds....correct?

Take another look at JPyle's trajectory chart. If you zero at 100 yards, the rest of the trajectory, before and after is lower. At 300 yards you're getting nearly a foot low.


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