HELP FILL OUT JB'S RIFLE ZEROING PAGE

[Firewall99]

Junior Birdman has a really useful rifle zeroing page (pg. 49) in his RBC POI, which has several knowledge gaps in it we need to fill out.  See below.  If you know any of the answers for the question marks, chime in!

I have recently updated the 10/22 information from my analysis of the manufacturer's manual and from brokensling's hands-on analysis, below.  They both match, at least for the 18" barrel.  Needless to say, if the new 10/22 sight adjustment information is correct, as I believe it is, we've all been using the wrong info.  We've been using 1 MOA per click, when it's really quite a bit less -- .625 per click, which works out to 5 MOA for every 8 clicks.

I have also posted the latest version of this page in .doc format, along with a text document showing my math, which I am told I should not be doing in public.  Better check it, you guys.

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AR15 variants:

Front sight posts                 Windage                          Elevation 
A1 20" = 1 MOA                 A1 20" = 1 MOA             A2 20" = 1 MOA
A1 16" = 1.5 MOA              A1 16" = 1.5 MOA          A2 16" = 1.5 MOA
A2&3 20" = 1.25 MOA      A2&3 20" = ½ MOA       A3 20" = ½ MOA
A2&3 16" = 1.875 MOA    A2&3 16" = ¾ MOA       A3 16" = ¾ MOA

** If zeroed at 25m with small aperture, zero is for 300m, large aperture is 200m

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SKS/ AK

Front Sight Elevation:    8 MOA per turn
Front Sight Windage:     Approx 1 MOA per .006" (Drift tool is approx .035" per turn)
Rear Sight Elevation:     Approx 3 MOA per detent out to 300m

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SOCOM M1A

Rear sight elevation =  1.5 MOA ?     Rear sight windage =  1.5 MOA ?

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FAL

Front sight:  ?
Rear Sight:   ?

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10/22 w/ Tech- Sights:     
                                             22" Barrel              20" Barrel            18" Barrel                  16"  Barrel
Front Sight Elevation:   .375 MOA/click¹     .5 MOA/click        .625 MOA/click²        .75 MOA/click
Rear Sight Elevation:     .375 MOA/click¹     .5 MOA/click        .625 MOA/click²        .75 MOA/click
Rear Sight Windage:      .375 MOA/click¹     .5 MOA/click        .625 MOA/click²        .75 MOA/click

1.  This is 3/8 MOA per click, or 3 MOA per 8 clicks
2.  This is 5/8 MOA per click, or 5 MOA per 8 clicks
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Ruger Mini 14
Windage= 1 MOA
Elevation= 1 MOA

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HK 91
Windage & elevation = 1.25 MOA per turn of the drum

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HK93
Windage & elevation = 1.6 MOA per turn of the drum

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Steyr AUG
Windage & elevation = 1.5 MOA per click

[Junior Birdman]

  Thanks, FW!

  And remember folks, this ain't heresay or "I once knew a guy who said" type stuff. If you HAVE one of these rifles and have "shot a box" to verify the moa per click, let us know!

[Firewall99]

I don't know how much I'm helping, because I just added some more question marks for all the known 10/22 barrel lengths.

However, it seems to me that these new questions, at least for the rear Tech-sight, may be subject to interpolation.  If the 22" is .8 and the 18" is 1, then the 20" would be .9 and the 16" would be 1.1.

Should we just go with those?

[MCKNBRD]

I don't know how much I'm helping, because I just added some more question marks for all the known 10/22 barrel lengths.

However, it seems to me that these new questions, at least for the rear Tech-sight, may be subject to interpolation.  If the 22" is .8 and the 18" is 1, then the 20" would be .9 and the 16" would be 1.1.

Should we just go with those?

Nah...don't guesstimate...  I've got a 16" barrel on the way to me, and I'm planning on having a day where I swap out AR front sight posts on 20", 18", and 16" barreled rifles, so I can get an idea what the 4 detent (A2 style) and 5 detent (A1 style) changes are.  Heck, if ya'll will agree to double my pay, I'll even add in the info about sight width for each on each rifle.   

If I could only find a 22" barrel to use...

Byrdman

[AFTERMATH]

Heck, if ya'll will agree to double my pay, I'll even add in the info about sight width for each on each rifle.

I vote to triple it!

[Bill 3]

My practical experience has yielded the following for 10/22's with Tech sights:

All ts100's

20" barrel rifle:  Rear windage and front elevation both ish at just over .5 moa per click

18" barrel rifle:  Rear windage and front elevation both ish at .625 moa per click

16" barrel rifle:  Rear windage and front elevation both ish at just under .75 moa per click

I don't own a 10/22 with a 22" barrel and haven't worked with one.  I have the three above.  My 20" is not a bull barrel and is no longer made by ruger in a standard contour but they are out there.

This differs from the numbers already given so anyone else please chime in with their experience.

Thank you - WRWIII

[Junior Birdman]

   I really think this table should be just for AR types since they have so many different possibilities. The other rifles are either easy or so rare that we can use the below method to determine IMC. It's been working well that way for a long time.

    When all else fails on ANY rifle, just have them assume 1 click is 1 moa and shoot the thing. (1/4 moa for scopes) Then have them determine what it REALLY is and adjust based on that.

[Fred]

    Good suggestion, JB.

    Does everyone understand that "teaching someone how to fish" always beats "handing someone a fish"?

[Bill 3]

    Good suggestion, JB.

    Does everyone understand that "teaching someone how to fish" always beats "handing someone a fish"?

Couldn't agree more Fred.  I guess this would be a threadjacking then.  Main reason I posted was the difference in results that I have had against what was already posted with 10/22's and tech sights.  Was wondering other's experiences.  If this should be some place else, let me know.  I think this good info for people to chime in on as they have become so common and alot of instructors carry them with as loaners.

- WRWIII

[ksuguy]

You might want to consider the different models of M1A.  The standard model has the 1 MOA sight,  the loaded model has a non hooded match sight with 1 MOA for elevation and 1/2 for windage,  and the national match model has a hooded aperture with 1/2 for both windage and elevation. 

[Junior Birdman]

  M1s and M14 types fall under the "easy" category. 

  The point is that the chart I started was for handing out to IITs at RBCs and IBCs to give them a head start on a little knowledge for teaching on the line. It wasn't meant for general consumption because of the "teach a man to fish" concept.

  I like the idea of having a good, correct chart for the BCs, but it shouldn't be a means of instructing or a crutch.  AR15 types, however........  
   Still, it's not hard to memorize them, and "help" the shooter arrive at the right IMC during the event in a way that will teach him how to do it for any rifle using the above mentioned method.

  Think of it as knowing the answer to the IMC question, but still making the shooter work through the problem and find the answer for themselves. You just feel better knowing the answer ahead of time.

  And also remember to NEVER trust what the scope/ sights/ shooter say about what 1 click actually is. We've seen too many cases of them being wrong, (Not as marked), especially with scopes and less expensive sights. Always prove it with actual holes in paper/IMC.

[Firewall99]

I heartily agree with the "teach to fish" concept.  We shouldn't use this chart as a crutch.

If one will remember, there is a point in our POI's, after the first sighter, where the POI recommends, "If someone is far enough off to cause problems, make a rough sight adjustment as needed to get them on the paper.  Don't zero it for them."

If we can get them at least on the paper in one COF so they can begin the learning process and not get frustrated, that seems like a worthwhile endeavor.   I personally would find the information on this chart helpful to allow me to do that.

I think all the common centerfire rifles should be included.  We see them often enough to feel the need, but not often enough for our less-experienced members to remember the settings for all of them.

[MCKNBRD]

Have to put my plan for 16, 18, and 20" barrels into the holding pattern, JB.  The guy I'm getting it from is volunteering at a church youth camp this week, and its going to be next week before I can get it.   

I'll post it ASAP, though.  Another thought...I use the DPMS Rapidex windage wheel on the Tech-Sights I install.  I'll check that wheel vs. the regular A1 wheel, too.

Byrdman

[MCKNBRD]

Whoop!!!! Just got that CUTE little 16" barrel in the mail today!!!...gotta do a little LTR 'smithing this week, maybe get my rifles out to the woods for a little 'sperimentin...

Here's my plan...I have 16", 18.5", and 20" barrels on different LTRs.  I'll use 3 A1 sight posts (regular, tall, and NM) and 2 A2 styles (regular and NM).  I'll see if I can get the differences between the tall and regular sight posts; gotta figure out how to make that work.  Also, I'm going to leave the stock A1 wheel on one of them, and use it vs. the DPMS Rapidex knob to see the differences in how many MOA a click is.  IIRC, there are 2 or 3 clicks on the Rapidex knob for each of the five on the A1 rear sight.

I'm planning on shooting an IMC box for each, and, if possible, I'd REALLY like to chrono the different barrels to see what the different lengths have for velocity.

Jeez...this is almost like a test flight...gotta make a plan for the whole day, seems like!

Byrdman

[Nickle]

OK, here's the AR info, right from the Army Field Manual.

What the Army calls an M16A2 or M16A3 is what we call a 20" AR with fixed carry handle.

What the Army calls an M16A4 is a 20" AR with a detachable carry handle.

What the Army calls an M4/M4A1 is a 14.5" or 16" AR with detachable carry handle.

What the Army calls an M16A1 is a 20" AR with 5 position front sight (round) and a fixed carry handle with no sight adjustments, or in other terms, identical to Tech Sights.

[douglas34474]

Who want's to go fishing?

The Tech-Sight has a 0.70 mm thread on the front sight post.

This equals 0.0275" of adjustment for ONE COMPLETE turn of the front sight post.
This in turn equals 0.0055" per 'click' as there are five 'clicks' on the front sight post. (0.0275"/5=0.0055")

Now you can figure out what this means to the POI with trig, but who wants to go there. All you really need is simple math.

With an 18" barrel a 10-22 has a sight radius of 23". At 25 yards you are looking at 900" to the target. What ever you do to the sight in the height adjustment, you will do to your POI by the ratio of 900/23, or 39.13.

Using that ratio, the one 'click' adjustment of the front sight post gives you a shift in the POI of 0.215" at 25 yards (75' or 900"). This would equal a 0.86 MOA shift.

For other barrel lengths you simply adjust the ratio and recalculate your numbers.

I ran the numbers and went to the range yesterday. The numbers work.

HTH

Douglas

[Junior Birdman]

  In other words.....1 moa per click?   

[douglas34474]

Oh well. So much for trying to teach someone how to fish.

[crak]

For you guys going crazy over .9, 1, 1.1 or whatever MOA...

1MOA @ 100 yards = 1.04719755 inches
1MOA @ 100 meters = 1.14522917 inches

The actual conversion of MOA to inches we use is ~ 5% off even at 25 yards.  Move it to 25 meters and we're a whopping 15% off!!!! 

So chill out.

But that's why you might hear some of us saying (when it comes up) that if you have a huge sight adjustment to make, take a click off for every 10.

[Nickle]

And, it's all approximate, as no sights are exactly the MOA value they say they are.

To put it in context for all of you, there's no such thing as a perfect group.

A guy up my way (either Lee or Allie Euber, they're brothers) holds the World Record for a group. Now, I'm not going to look it back up for exact details, but it was an IBS (International Benchrest Shooters) record. It was either 100 yards or meters, and IIRC, it was a Heavy Varmint (13.5 pound class) rifle, almost certainly 6 PPC caliber. The group size was about .050". That's the record, and it isn't .0000".

So, the click value isn't exact, the rifle groups aren't perfect (no matter what rifle you have) and the MOA value isn't exact. The shooter isn't perfect either.

Son of Martha says "Perfect is the enemy of good enough" and Nickle says "Close enough is close enough".

And, so clicks that are close are good enough, like many of us have said.

[Talon]

  In other words.....1 moa per click?   

Silly Birdman. Clicks are for Trig.

[Devnull]

Bwahahaha!