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50yrd AR-15 Iron Sight Zero

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DyNo!   

You might hit them somewhere.

Zero at the longest distance you have access to.

Edited by DyNo!

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xm193gt9.jpg

Keep in mind your close shots are going to have a lower POI than POA because of the sightline/boreline offset at the close in ranges. If you're using a standard front sight base with a flip up rear or similar, I believe it is 2.25" offset at the muzzle (but don't quote me). It's a much flatter trajectory out to the 225ish range, but with a 16" bbl at around 3000fps your 250yd drop is appx. 3.7" and the 300yd drop is appx. 9". Will depend on barrel length, muzzle velocity, etc. Basically you'll hit A/0 zone from 0-250 as long as your POA is good at the center of the zone/ring but will have to creep up to the top of the A/0 zone or throat area for the longer shots. If they are known distance targets I'd do into it with that mentality, but I'd rather aim a little high and still chance the B/1 shot than waste time ranging it if it's not known between 225-300.

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I was told 50yrds was improved battle sight zeron for 300meters

You're looking at a 25/300 zero vs a 40 or 50/200 zero. 40-50/200 is flatter out to just past 200 but drops more after that. 25/300 has much more rise at the 150-200 range.

25/300 zero:

xm19325if8.jpg

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George   

50 yard close zero = 200-225 yard zero downrange. BUT do not rely on 50 yard zero, always confirm it at the longer distance as little things amplify farther away ;)

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George what do you mean? I had an inch group at 25 so that has to mean it will be an inch at 200 right? ;) What do they mean minutes of angle... time is not involved in zeroing is it?

Edited by cardiackid

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I zero at 50, then confirm at 200. At 25 it's 1.5" low, at 225 it's again 1.5" low. At 100 it's a little over an inch high. At 350 it drops 12".

I shoot 52gr from a 20". With irons and an A2 style rear sight drum I had both 25/300 and 50/200 zero's set up. Turned the elevation drum 9 clicks up, then reset the 3/6 portion of the drum. For 50/200 I bottomed the drum (9 clicks down), for 25/300 I set the drum on the 3/6 setting (9 clicks up from bottom). For close range hoser stages 25y and in I set it on 3/6 mark. POA=POI at 25. If I came across a 400 target I turned the drum past the 3/6 mark and stopped on "4". This made the sight versatile for many different ranges. Nothing beats confirmation though.

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lugnut   

I'm not a big rifle shooter yet but this is good stuff. I guess I have a question why someone would bother adjusting the rear sight for any shots between 0 and 2oo yards. Of course after that distance holding over would be tricky so I can see that.

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George   

George what do you mean? I had an inch group at 25 so that has to mean it will be an inch at 200 right? ;) What do they mean minutes of angle... time is not involved in zeroing is it?

If you are printing one inch at 25 yards, then you are beyond help here LOL

Seriously, MOA is an easy thing to understand. One MOA is one inch at 100 yards. This translates to 1/4" at 25 yards, 1/2" at 50 yards, 2" at 200 yards and 3" at 300 yards. If you and your rifle can hold one MOA then these are the group sizes you should be printing at these distances. Most folks have a hard time holding any better than 2.5-3 MOA even if the rifle is capable of better ;)

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I was only joking about the MOA stuff - You'd be astonished how many people I work with on a daily basis in the Army that have never heard of it or understand the concept :surprise: Then again 90% of them will never shoot beyond 300m so from their standpoint it's ignorance is bliss as long as the target falls down (even though the shooter grazed it on a shoulder.) The graphs I posted were pulled off a google images search - for some reason it paints the picture of trajectory in a much better explanation than a spreadsheet that shows the rise and drop over sight line. Explaining to someone how a 2 or 4 MOA red dot optic works over distances and why they need to zero their lasers a certain way is like pulling hair out most of the time. Then again, I'm sure an NCO was saying the same thing when I was learning :)

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I'm not a big rifle shooter yet but this is good stuff. I guess I have a question why someone would bother adjusting the rear sight for any shots between 0 and 2oo yards. Of course after that distance holding over would be tricky so I can see that.

I adjust it based on the stage I'm about to shoot. Nothing further than 25y (it happens), I set it for my 25y zero (no hold over). Less thinking, faster shooting.

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DyNo!   

I'm not a big rifle shooter yet but this is good stuff. I guess I have a question why someone would bother adjusting the rear sight for any shots between 0 and 2oo yards. Of course after that distance holding over would be tricky so I can see that.

I'd go even further and say 0-300 since even with a 200 yard zero, fast moving .223 only drops about 6-7 inches and if the target is 2MOA, you might actually be able to hold at the top of the target.

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Big Bore   

I was told 50yrds was improved battle sight zeron for 300meters

Only for people/soldiers who don't get out and don't have the opportunity to shoot.

If thats what you have (50 yards) it will get you on paper and adjust from there at distance. Shoot at different known distances so you know exactly where you will hit and how you have to hold.

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Big Bore   

I'm not a big rifle shooter yet but this is good stuff. I guess I have a question why someone would bother adjusting the rear sight for any shots between 0 and 2oo yards. Of course after that distance holding over would be tricky so I can see that.

I adjust it based on the stage I'm about to shoot. Nothing further than 25y (it happens), I set it for my 25y zero (no hold over). Less thinking, faster shooting.

All that adjusting will get you in a bind especially if you forget to set it back when your done. How do I know that? Try hitting a 100 yard target after you forgot to dial back after shooting 600 yards. That hurt me bad enough at a big match to put me in 2nd place.

A 300 yard zero that you have shot and verified at known distances will become automatic and quite fast with time. I don't adjust anything until I'm past 400. I can hold top edge of a 400 yard plate and put it down.

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You might hit them somewhere.

Zero at the longest distance you have access to.

I have access to a 600 yards range should I zero at 600 yards? (Devils advocate) I say pick a zero that meets your match needs.

Pat

Edited by Alaskapopo

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DyNo!   

You might hit them somewhere.

Zero at the longest distance you have access to.

I have access to a 600 yards range should I zero at 600 yards? (Devils advocate) I say pick a zero that meets your match needs.

Pat

If you dialed up to a 600 yard setting and zeroed - and dialed back down to 200 or 300, I bet you'd be better off with that than a 50 yard zero. I do understand your point though and agree that the OP should prepare for the longest shot he has to take. :cheers:

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I've always zeroed at 50 and confirmed somewhere between 200 - 225yrds. Typically have to fine tune it a little at the 200yrd line, but seems to have worked pretty well for me compared to guys that zero at other distances. I think the biggest thing is know your zero and shoot it at different yardages so that you know where your rifle shoots with your ammo at those distances.

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So if you sight you irons in at 50yrds w/ 55gr fmjbt where will u likely aim to hit idpa targets from 10-300yrds??

Dead on to about 200. Aim at the head at 300.

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Billski   

If your matches have 300 yard plate racks (Lucky people if you have matches with that kind of room) you will need a 300 yard zero and then know your hold overs closer.

If on the other hand your matches never extend past 200 yards and most of your stuff is up close and personal, a 200 yard zero works great. We primarily shoot the IDPA target around here, and the 200 yard zero means hold 2" low at point blank, "on" at 50 yards, around 2" high at 100 yards, and "On" again at 200 yards. One time, I fired the NY State USPSA rifle match with 3 shots at 330 m on strobe light equipped targets. I used my 200 yard zero, and I just held the top of the target for those very few long ones. Worked perfect.

Billski

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KentG   

George what do you mean? I had an inch group at 25 so that has to mean it will be an inch at 200 right? ;) What do they mean minutes of angle... time is not involved in zeroing is it?

If you are printing one inch at 25 yards, then you are beyond help here LOL

Seriously, MOA is an easy thing to understand. One MOA is one inch at 100 yards. This translates to 1/4" at 25 yards, 1/2" at 50 yards, 2" at 200 yards and 3" at 300 yards. If you and your rifle can hold one MOA then these are the group sizes you should be printing at these distances. Most folks have a hard time holding any better than 2.5-3 MOA even if the rifle is capable of better ;)

Amen. I can hold sub moa at 50 off of a bench with a grip pod on my JP/Meopta as in multiple holes touching/same hole. At 200 I can do MOA but the dot is hard to be precise with even at 4X. Like folks say for multigun minute of man is good. Hit a flasher at 300 (around here) and your good to go.

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KentG   

I've always zeroed at 50 and confirmed somewhere between 200 - 225yrds. Typically have to fine tune it a little at the 200yrd line, but seems to have worked pretty well for me compared to guys that zero at other distances. I think the biggest thing is know your zero and shoot it at different yardages so that you know where your rifle shoots with your ammo at those distances.

THAT is the biggest thing. Know your POI at your max available and everywhere in between.

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kurtm   

Well take this all with a grain of salt, as I never shoot iron sights, and really don't know about ballistics but when I bother to zero my rifle...which is almost never cause I really don't know how. I run a 300 yard zero and my cross over point is right at 50 yards....not 25! Now I know all the ballistic charts and wonder graphs say I am lying to you, but this has held true for every 20" extended sight radius rifle I have owned, built, or shot, so like I say take it all wiht a grain of salt....but it is far better to check it at the range you intend to be zeroed at, and don't trust any graph or chart! KurtM

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Nuke8401   

KurtM,

I just sighted in my 20" extended sight gun at 200yds, 25" sight radius. I am hard pressed to find a 300yd or more range here in the north east. My hillbilly calculations are telling my +6 clicks for 300, +12 for 400, +23 for 500. Does this sound close for XM193? DPMS rear sight with with 3/6 knob? I also had to cut the front post down significantly to be able to bottom the rear sight for 200, sound normal?

Even though you don't shoot irons much your opinion would be appreciated. ;)

Thanks,

David E.

Edited by Nuke8401

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