temporarily adjusting for 25yd distance with AR zero'd for 50yd. in repeatable manner

[gidaeon]

I am using a mid-length 16" flattop AR with irons and presently have a 50yd. zero.

I would like to quickly be able adjust POA=POI when moving between 25yd. and 50yd. Is there quick, repeatable way to do this with my setup rather than adjusting holdover? I would rather not be moving my front sight every time I go to another Appleseed or have to change range lanes, but am not yet familiar enough with this to understand if its doable with a rear sight adjustment alone?

My elevation dial is presently on "4". Is this supposed to be 6/3 for my 50yd. zero?

A few issues I see with my lack of knowledge here:

1) I have no idea how much a click on the front sight raises or lower my POI at any given distance.

2) I do not know the relationship of clicks to moa on my rifle (CAA rear iron sight uses half clicks)

 

[gamestalker]

The best way to accomplish this is to first determine an approximate muzzle velocity of the ammunition being used. I wouldn't concern myself with the B.C. of the bullet considering your not using optics, but irons instead. Once you determine that, you can then zero it to the correct distance, be that 100 yds. or what ever. When it has been zeroed properely you'll have very little variation when going from 25 yds. out to the zero distance, which will likely be some where around 100 yds. to 150 yds.. The problem with zeroing in at close range like 25 yds. to 50 yds. with a higher velocity round, is extreme elevation variations are unpreventable because the bullet is crossing the line of sight to soon and will have a second zero that will be at a relatively greater distance, while everything at closer distance is going to be experiencing large variations as well when going from 25 yds. or so to 50 yds. and out, until it finally crosses over line of sight again at what will be a much farther distance than the actual zero for that velocity round.

 

[LKB3rd]

50 yards is roughly the same as your 200 yard zero, and 25 is roughly the same as 300.
So, you could get a 25 yard zero by going up from your 50 yard zero. I don't know offhand how many clicks it would be, but you could spend a range session to sort it out.

Bad drawing, but hopefully you get the point :/


If you set up the sights the way they were designed to be used, the 6/3 when at the bottom is 300 meters, and your "battle zero." This is because it will get you within a couple inches of point of aim from point blank all the way to 300 meters. The 4, 5, and 6/3 at the top are 4 5 and 600 meters. To zero it for this method, look for the tiny "z" which is a couple clicks above the 6/3 and zero that for 25 meters. The others should be on when you do that.
Some people use othert methods, including one where you loosen the adjuster, and set it up to have 4 clicks below 6/3, which is then zero'd for 50/200. Then you go up to the 6/3 for your 300, and so on. This method might work for you.

 

[wanderinwalker]

Just turn the elevation adjustment drum as needed. Write down the settings for each range and you're good-to-go. It's not super complicated but effective.

 

[LotI]

For point-shooting at close range, you can use the top of the rear peep sight and the front post.

In other words, don't look through the peep...use the top radius to line up the front sight. Not super accurate but you're only at 25 yards.

 

[Andrew Wyatt]

First, I would rezero the rear sight so it's properly zeroed at 50. Right now, you have the 400yd sight setting set to 200. I'm not familiar with the A2 style sight, but there should be a setting several clicks below 6/3 which is what you use when zeroing at 50.

The other thing to look at is the aperature on an A2 sight has an elevation change between the small and big aperture. It may be as simple as switching from big to small to get your zero.

 

[KW]

See this post by Molon on AR15.com: http://www.ar15.com/forums/t_3_18/328143_index.html

You need to use an allen wrench to adjust your elevation wheel to allow travel below the 6/3 setting. You can then zero at 100 yards at 6/3 -6 clicks, or 50 yards at 6/3 -4 clicks, or 25 yards at 6/3 +5 clicks or so. The link above goes into great detail on how to do this.

P.S. Keep in mind that all his values are for an 8/3 fixed carry handle sight. Double the click values for a 6/3 removeable carry handle sight.

 

[gotigers]

It sounds like your question has been answered, but a bit of advice. Try to find a local Service Rifle Match. These guy know there stuff and are usually more than willing to teach you the "come ups" and windage. These matches are easy going and fun.

 

[rcmodel]

quickly be able adjust POA\POI when moving between 25yd. and 50yd.

As everyone else has said.
There is absolutely no reason to change zero between 25 & 50 yards if you are sighted in at 250 yards in the first place.

The difference would be less then an inch, and unless you are shooting flys off your target, you can easily hold off for that amount without changing the sights.

rc

 

[MtnCreek]

If you depend on this AR for home defence, I would suggest learning to hold over when shooting inside your near zero.

Edit: Sorry, I didn't know what Appleseed was.

 

[arizona98tj]

Most of you haven't shot an Appleseed shoot, at least it seems so based on the comments. If you have, you're not thinking about how small those 400 yd scaled targets are.

The 400 yard target, at 25 yds, is less than 2" high. The 5 point scoring zone is but 3/4". Being off an inch can take you from 5 points to 0 points (actually, double those points that since the 400 yd targets count double).

So...the OP really needs to be able to dial in the sights for 25 yards.....and, as RC mentioned, be able to shoot a fly off your target.

Learning to hold over for a 2 day event, such as Appleseed, isn't practical in my opinion. Holding over gets you close enough for a handful of shots for a HD situation (that is how I train), but doing 400 rounds in that fashion, shooting for an Expert marksman score, makes it pretty hard to obtain. I wouldn't want to do it.

 

[gidaeon]

Thanks for the input so far. Arizona98tj is correct, I am shooting at 1in. squares for practice when at 25yd., so being truly dialed in is very important to me. Hold over is not good enough (for me anyway) for the timed AQT's.

This will be my 5th Appleseed. Usually I sight in the gun just before the weekend but I want to be able to quickly adjust for times when I show up at range and 25yard is not available but 50 or 100 is. I did a cmp high power clinic recently and hope to continue learning such, I only shoot my m1 at 100 yards and have never changed my AR sights once "set" at my given distance.

I just don't know enough about my sights and how to best setup to meet my stated need. I'm working through the suggestions and especially the RIBZ link on arfcom.

Yes! Thanks KW, this link is exactly what I needed. Now to see how works out with my rifle\sights\ammo combination but at least I have a ballpark once I have sights readjusted for 50. http://www.ar15.com/forums/t_3_18/328143_index.html

 

[henschman]

An AR-15 with A2-style sights and a carbine-length sight radius has approximately 1.5 MOA clicks on the front sight (its actually some wierd fraction, but 1.5 MOA is pretty close). Remember "FORS" -- front opposite, rear same -- so you adjust your front sight in the opposite direction you want your group to move. It has standard pitch threads, so turning the post left will raise it, and turning it right will lower it.

The rear sight windage drum has approximately 0.75 MOA clicks.

The rifle is designed to be sighted in at 25m/300m with the rear sight elevation drum set for the 6/3 setting (which is usually with the drum all the way bottomed out), and using the small aperture. You use the front sight to zero your elevation, not the rear sight. Once you have this zero, using the small aperture, the bullet drop compensator on the elevation drum will be correct for every distance from 300 out to 600m. To go to your 50m/200m zero, put the elevation drum on the 300m setting and flip to the large aperture. The standard surplus round drops 2 MOA between 200 and 300m, so the large aperture is 2 MOA lower.

The large aperture is designed for use on man-sized targets at close range. It does not allow for as much precision in aiming as the small aperture. For shooting inch squares at 50 yards (a 2 MOA target), you may want to use the small aperture and just adjust the front sight up 1 or 2 clicks (whichever gets you closest).

FYI the standard come-ups in MOA for an AR from 100m to 500m are 2,2,3,4.

Hope this helps!