I'm referring newer shooters to this thread all the time. It seems to be a confidence builder in understanding the A2 sights, and I think we're getting more motivated AR shooters because of it.

Thanks, Molon!

edit: page pwnage

So if your sight is marked 6/3 everything should be doubled? Ok so when you pull that set screw and you adjust the sight by 4 clicks (3 for the adjustment 1 for the buffer) does that mean on a 6/3 unit that moves in halves should be adjusted 8 clicks?
I have a LMT A2 BUIS that is marked 6/3 so I just want to make sure I am following instructions correctly.

Correct, everything is doubled in terms of adjustments.  (1/2 MOA vs 1 MOA)

However, the "buffer" on a 6/3 need only be 7 clicks unless you feel better about using 8. The only purpose of that is to ensure it has no pressure on the elevation index at the lowest setting.

This thread has been really helpful (Thanks Molon).

I currently have access to 25y, 50y, 100y, and 200y ranges. My club just finished a 600y range that I need to qualify for in order to use. I will need to qualify at 200y, 300y, and 600y. At 600y, this means going 10 for 10 in a 30" ring, with room for a few initial rounds to get on target. I've read this thread multiple times and I think I understand everything, but would just like confirmation to make sure I do.

My system is a 16.25" barrel, 1/9" twist, 14.5" sight radius, with a detachable rear sight (6/3), but no carry handle. I use the small aperture and Lake City M193.

If I set my rear sight up according to the RIBZ guidelines (potentially requiring the longer front post) and then zero at 50y with the rear elevation set at 6/3 -4, I should be reasonably on target at 200y (6/3 -4), 300y (6/3), and 600y (6/3 again, but +1 full clockwise rotation of the rear elevation wheel from the 300y setting). Is this correct?

Because of the ranges I currently have access to, I could shoot this set up at 100y (6/3 -6) and 200y (6/3). If I am on target at these distances, this should be somewhat of a physical confirmation that I'm likely to be on target at the 300y and 600y distances, correct? (In other words, this should confirm that my elevation wheel is calibrated with reasonable accuracy)

I just want to make sure my thought process is correct before attempting to qualify, considering that I will not be able to shoot beyond 200y prior to attempting to qualify.

Thanks!

-MC

(Continued from above due to the new member word count limit per post)

Lastly, if I need to make finer adjustments to bring myself on target at longer distances, I can do this by making single-click adjustments with the rear elevation wheel. Prior to reading this thread, I was under the impression that a 6/3 elevation wheel with a 14.5" sight radius should result in .75 MOA adjustments per click, but this thread appears to say each click should be .5 MOA? Any idea which of these is correct? I've sent this question to the firearm/sight manufacturer, but who knows when or if I will hear back.

Thanks!

- MC

You should be close, but will notice a difference beyond 300. remember this system is for the 20" barrel using a rifle sight radius and 62gr ammo.

that said, the differences may be a couple of inches of at all. If you have access to 200 now, I'd recommend setting up the zero per the instructions, then test point of impact upon adjusting the click values. The drop should give you a better indicator of what your adjustments actually mean per your system.

ballistics aside, I don't like your ranges policy of making you "qualify". that detracts from new shooters getting involved. not saying you're new to shooting, but imagine someone who was. how could they get better if they can't practice?

test your setup at the ranges you can and compare with the ballistic drop graphs early in this thread. then when you get out there, let them know you're running a zero that may require adjustments as you shoot it.

If the point of qualifying is to show competence, then once you adjust your impact point you can hold a group to demonstrate "competence". ( sorry but your range is silly)

Also. .. just noticed again you are qualifying on a 30" target. you're good to go. test your drop,  but I use this system to hit 24x24 plates out to 500 wroth no issue.

Thanks for the reply ank!

Great info, thanks Molon.

Did the RIBZ mod and installed the taller front sight posts on both weapons at the same time. I put the new posts in with their bases about 2 clicks lower than the originals. Sighted-in at 50 yards and needed to go down 2 - 3 clicks more. Went out to 100 yards, set "8/3" -3 and "6/3" -6, and put rounds right on target.

So I have read all 19 pages over the last few days and I'm glad to be finished, but glad that I read it all. I have completed the 6/3 half clicks modification to 6/3-8. I have pressure and/or bottomed out on -8 so -7 is my buffer. My most recent build, a 14.5 middy, was built with the intentions of staying an iron sights trainer for a while, until I've got it down. Unfortunately I just made a big range trip before I found this and it will be a few weeks before I can get back to an appropriate range to test all this great new info.

So a few observations I found in reading the whole thread.

1) many seemed confused about the difference between the actual modification to the sight put forth by Molon and the merits of using the 50/200 zero concept.

2) many people seem overly concerned about what setting to dial in for accurate hits at 25 yards. Heads up folks. This is a battle zero, not precision. If you have cause to use your rifle at 25 meters/yards/feet/inches are you going to be dialing you elevation from -4 to +5?? Or are you going to want to know where your rounds are gonna hit at close range and adjust accordingly on the fly?

3) reading the whole thread got easier when I realized I could skip any question about how to better use your large apiture. For goodness sakes people just use the small one. Or better yet zero with the small one... Then just flip to the large one and see where they are on paper.  It's going to be different for every barrel length, sight radius, velocity, bullet weight and large apiture height. Just get out and try it.

Can't wait to put my money where my mouth is and make this happen. Thanks Molon for sharing this and the Mods to keeping it accessible.

This tread alone is the reason I keep carrying handles with my rifles.

With an allen wrench you can tweak the rear site to enable you to have adjustments in distance at 25,  50, 100, 200, 300, 400, 500, and 600.  The significant distance being 100 since that is the distance of most outdoor ranges.

Taken from the first post on this thread by Molon:

+++++++++++++
Now that you have moved the elevation knob 4 clicks clockwise, taking care to make sure the elevation index wheel has not moved, firmly tighten the index screw. Starting with the elevation drum at the 8/3 setting, you should easily be able to turn the drum counter-clockwise 3 clicks and see the rear sight base moving down. (You should be able to turn the elevation drum one more click counter-clockwise for our “buffer zone.”) You are now ready to head to the shooting range.

As I mentioned earlier, this sighting scheme is really just taking the Improved Battlesight Zero one step further. Starting with the elevation drum at the 8/3 setting, turn the elevation drum counter-clockwise 3 clicks (8/3, -3). This is your 100 yard point of aim equals point of impact setting. From a distance of 100 yards, zero the rifle with the rear sight at this setting (using the small sight aperture). Do not change this rear sight elevation setting while zeroing. Use the front sight post only to make changes in elevation while zeroing.

The beauty of the RIBZ sighting scheme is that once you have zeroed the rifle with this method, you will have your 100 yard zero setting and the other settings of the elevation drum remain intact (within the limits of the coarse adjustments of the A2 sights). If you want to use the Improved Battlesight Zero, simply set the elevation drum to 8/3, -2 and you're good to go. To use the standard military 300 meter setting, just set the elevation drum to 8/3. You can also start the zeroing process by obtaining the Santose Improved Battlesight Zero at a distance of 50 yards with the rear sight on the 8/3, -2 setting. Obviously, slight variations will be encountered depending on the ammunition used and the actual amount of movement with each click of the various sights. The results will certainly be close enough “for government work.”

When using this sighting method, you may find that once you have set your 100 yard zero, the top of the base of the front sight post is now slightly above the top of the well in the front sight base. If this happens, the “0.040” taller” front sight post from Bushmaster provides a quick and inexpensive fix.
+++++++++++++++

On the last paragraph, he describes this is what has happened on an A2 with fixed carry handle and standard FSB, and he recommends to use a 0.040" taller FSP from bushmaster.

Now since I have a Colt AR15A4 with detachable CH, but with an non-F FSB,will I have issues sighting in with bushmaster's 0.040" taller FSP now that the rear sight base has been set at 100 yard zero (6/3, -6 setting)?

Does this also apply to the LMT fixed rear BUIS?

I tried this today. But only the 25yd was available. After following instructions on first post and setting my A4 CH to 6/3, +6 I was able to zero it.
But the base of bushmaster 0.04" FSP on my non-F FSB is almost screwed in at the bottom.
Since the the 50yd is not available and only the 100yd gong is, I was able to hit it with 6//3, -5 setting.

I was thinking the way the bushmaster FSP setting was zeroed, I don't think that I don't need it as I didn't really need that extra 0.04".
Is this really the case? It's an Colt AR15A4, non-F FSB.

Also anyone has a link for the 25-yd zeroing target similar to the 100d and 50s used on this thread?

Yes.

I have done this to my A4 (20" and carry handle) and the sight settings are spot on for M855 (Greentip).

The question though: has anyone had the opportunity to try this with M855A1, the new EPR round?

Good info.....can't believe I forgot about this post for so long.

Last year Anthony Williams in the Small Arms Defense Journal said the G7 of the new M855A1 bullet was 0.152, not much different than the 0.151 of the original M855 bullet.

ATK says the M855A1 bullet has a G1 of 0.307, again not much different than the 0.304 of the original M855 bullet.

I have screwed up and need a little help correcting my goof.
I set everything up for my 6/3 lmt rear sight. However when I hit the range I did not use the 6/3 -6 clicks for my 100 yard zero. I accidentally left the drum at 6/3 so now I gotta go back up reset things...or at least ball park em for now before I can hit the range. For now though if I set my drum for 6/3 -6 Would I need to raise my front sight (Samson rail mount fixed unit) up 2 or 3 clicks? I just need to ball park and ill fine tune later. Thanks for the help guys.

If the click adjustment value is the same as the standard FSB, then it should be two clicks.

6/3,-6 = 3.4" at 100 yards

2 clicks of the FSB = 3.3" are 100 yards.

Close enough.

Thank you sir!

If you have a fixed handle 16" carbine with a 8/3 rear drum sight what RIBZ would you use? The 8/3 setup?

From page 5

"For a 14.5” sight radius with A2 upper, the elevation clicks are worth 1.43 MOA each"

Given the coarseness of adjustment a 100 yard zero would be the same, 8/3, -3 A 200 yard zero would also be the same, 8/3, -2.

Thanks for the follow up info.

Da nada.


...

That warms the cockles of my heart.

..

Try it now.


...

Yes, although it won't be perfect (none of this is.)


...

And since they're still screwing with the velocity/pressure of M855A1, the difference is probably insignificant.


...

Bump for great info.

btt

After recently purchasing a removable carry handle, I have read this thread-- and others around the internet, dozens of times. Incredible source of information and knowledge.

I did have an inquiry to bring to the table:

Assuming a removable carry handle on a carbine is properly configured for the RIBZ,(so eloquently laid-out by Molon) and then zero'd at 25 meters on the 6/3 setting, utilizing the smaller aperture, your numbers should be:

-------------------------------------------------
25 meters: “6/3”
50 yards/200 meters “battle zero”: “6/3 -4”
100 yards: “6/3 -6”
150 yards: “6/3 -6”
200 meters: “6/3 -4”
300 meters: “6/3”
400 meters: “4”
500 meters: “5”
600 meters: “6/3” after one full rotation upward
-------------------------------------------------

It may be a moot point, but if I am learning a system I want to know all of it-- is there a way to determine what these numbers look like utilizing the larger, 0-2 aperture?

FWIW
I found the 8/3 RIBZ tuning on rifle length A2 platform was very easy to dial in at each distance.

Is this due to the mechanics of the 8/3 design for 20 inch barrel?

The 6/3 on rifle length A3 took some work to get each distance tuned.

What has been your guys experience?

I really like the RIBZ solution!! Thanks to all for such great information!

Do you mean verifying zero using the BDC adjustment? The 6/3 is probably calibrated for M855 from a 14.5" barrel (I forget if the A4 came before M4).

Yes sir.

this thread is dizzying to me

after a while it just becomes #####s

relevant info
I have a detachable carry handle 20 inch rifle length ar.

I want to have an keep a 25 yard zero as the base, but still be able to reach out up to 300---primary usage is hd, secondary usage for the longer distances would be just to learn, have fun at other ranges

set 25 yards at 6/3--this would be where I would set the near zero at the 25 yard range  ( for the hd purpose)

then add 4 and 6 to the normal +5 of how molon described it
=
go -9 for 50 yards
go -11 for 100 yards
go --9 for 200 yards
go to 6/3 at 300 yards

and just forget about 400 yards?

I plan on writing the dope on a piece of tape on the side

does this sound right?

Non f marked fsb if that matters

Thats a bit confusing.

Loosen your set screw and adjust so the drum can rotate -4 clicks from the 6/3.

Your detachable handle has a Z mark on the drum correct? For all intents and purpose that is your 25 meter/yard zero. The z should be two clicks up from 6\3.

Zero at the Z for 25 yards.

Then you can go back to 6/3 for 300 yards, 6/3 - 2 for 50/200 yards 6/3 - 4 for 100 yards.

Its not perfect, but that should put you in place the right place for shooting from 25, 50, 100, 200, 300 and then dial up from there.

Ok didn't see where you need to roll the drum down on detachable carry handle

I have a z mark but it is rotate counter clockwise from 6/3. -2

For a 20 inch a4 detachable carry handle,  what are the dope points away from 6/3 to get to

25, 50, 100, 200, 300 yards?

go -4 for 50
go -6 for 100
go --4 for 200(ish)
go to 6/3 +5 for 25 and 300 yards?

Correct?

- is counter clockwise and

+ is clockwise correct?

I just reviewed my drops on Strelok.  yes the -4 -6 -4 clicks are all correct for m193 out of a 20 inch barrel with a detachable carry handle.

6/3 is 300 yards. 6/3 + 2 should be the 25 yard zero iirc.

The + is rotating clockwise and the - counter.

Remember in case you havent reviewed it. You have a near and far zero. The trajectory relationship between the 50 and 200 yard zero is why they are both -4 clicks.

I think I am "getting it" after reading https://savannaharsenal.com/2017/04/08/how-to-zero-ar-15-a2-type-sights/

From that link
Rifle with 20″ Barrel and Removable Carry Handle:

25 meters: “Z” setting
50 yards/200 meters “battle zero”: “6/3 -4”
50 yards: “6/3 -4”
100 yards: “6/3 -6”
150 yards: “6/3 -6”
200 meters: “6/3 -4”
300 meters: “6/3” (or “8/3″ with fixed carry handle, 20” barrel rifles)
400 meters: “4”
500 meters: “5”
600 meters: “6/3”

So my question is
can you lower the drum minus 6, and zero at 25 meters on the z?

then use the same dope numbers above for the other distances?

I know bullet weights etc will change it, but to get me in the ballpark?

Yes you can. Your front sight will adjust to allow you to zero at the Z mark and still use the various sight settings all up and down the drum.

I have a non F fsb and a mil carry handle and I zero fine.

Thank you

I adjusted the bottom drum -6 clicks today

went well, now to go zero on the z at 25