DISCLAIMER: (This post asks questions that could probably be answered by a succession of SEARCH uses over time. As this is a discussion thread, and every question has been asked before SOMEWHERE, please refrain from replies like 'USE SEARCH UGH')

Happy Holiday Monday to all at ARF!

The Skinny: So - I've purchased my very first LPVO, a Sig Tango MSR 1 10X26 FFP, and I have some questions about sighting in. (Yes, there is LOTS of info online, each individual tidbit claiming to be the RIGHT way despite being frequently contradictory, and most of it relying on a foundation of knowledge I frankly find unlikely in someone who has just purchased their FIRST LPVO..... so I'm coming here straight to the experts lol)

The Background: I have only recently started working with the AR platform and have only ever used Red Dots and 3X magnifiers. I know absolutely NOTHING about ballistics and I am just now learning about different reticles. (Again, there is a ton of info online, but I am searching for a SINGLE online reference resource I can use to learn from as I go along... recommendations are appreciated. Even a good old-fashioned BOOK would be best)

The Gear: Sig Sauer TANGO MSR 1-10X26 FFP, Daniel Defense DDM4 V7P, a Caldwell adjustable rest, a premium laser boresighter, Vortex SOLO 10X Monocular, sighting-in paper targets, and several premium ball ammo choices in 5.56

1) What is the right distance to use when zeroing, bearing in mind I am trying to push my abilities out from 100yds to 300-400yds eventually?
2) The Tango MSR uses what Sig calls a "BDC-10" reticle, where can I find more RELIABLE and new-user-friendly info on this reticle?
3)The proper procedure to use?
4) Anything else I should know?

My thanks in advance for any help and advice!




*PS - Despite the availability of a variety of digital and app-based assistants in this realm, I have absolutely NO interest in them. I want to learn how to do this MYSELF, with pad & pencil if necessary.

The instruction manual should give you directions on how to zero in order to best have your ballistics line up with the reticle. This will be dependent on your ammo and barrel length. A reticle such as the BDC in the MSR is not a precision reticle, but more of a DMR reticle.

read the manual, but the holds are based on a certain zero if a BDC.  I would guess 100Y zero, and do it at MAX magnification.  then your BDC holds will correspond to 200/300/400, etc.  If it's SFP then the values are only good at MAX mag.  

make sure you take time to check your height over bore at close distances at 1X.

good luck!

IMO, the BDC holds in the charts will just get you close. There are so many variables that they won't be spot on so you have to shoot at each yardage to see where your gun/ammo combo hits. Some guys will use fancy apps to figure holds but you really need to actually shoot at those ranges to be 100% sure.

I'd throw the bore sighter away(just never had good results from them) and just start at 50yds with a large piece of cardboard behind the target so you can see the hits. Get it close at 50 then move back to 100 for the final zero. Then shoot at 50,200,300, and 400 to see where it hits

ETA. Id save the premium ammo for the final adjustments. Get it close with cheap ammo first.

Read the manual. Usually, these BDC reticles are designed to be zeroed at 200 yards, with the marks below corresponding to 100 yards increments (300, 400 etc).

Agree with others the manual will be your source of correct distance to zero.  On that I will also say just because the manual says do X does not mean that the BDC will line up with your rifle and ammo.  That is where verification and DOPE come in because the BDC is best approximation but verification is key.  Example the 300m/yrd subtend could actually be 320m or 275m but you will not know till you test it and see if you are high or low at that range.  Just because it is not spot on at the range it says does not mean something is wrong it is a data point and you should record it.  The records will be your dope and when you take that shot again you will know you will be Y high or low and you can adjust your hold for that.

Agreed, read the manual.

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I’m going to sixthly say to read the manual that came with the scope.  Every scope will be different and they will recommend a zero distance with one  grain of ammo.

Personally, I don’t think manuals are very useful for zeroes and ballistics as your ammo choice and barrel performance needs to match what the manufacturer used for their BDC.

If you’re going to be shooting at distance, I think it’s very important to find the actual velocity of your ammo with a chronograph and plug that into your ballistic calculator. They don’t cost that much and you’ll use them often if you change ammo often.

The manual is where you start not the definitive answer but best approximation to get going.

In defense of the OP, the manual doesn't say much at all about the reticle.

https://www.sigsauer.com/media/sigsauer/resources/21SIG3367_TANGO-MSR_7402825-01_R01.pdf

I did find the following on Sig's FAQ page

https://www.sigsauer.com/faqs

Then why are you asking us?

....

Probably because they don't want people to know what garbage that reticle is for 5.56/223 Remington.

...

I’d recommend reaching out to Sig, but when I did the formula they gave me equated to drops that would work in a BB gun. They tried to be Primary Arms and didn’t do too good at it.

With an AR you’ll need to look up ballistics for your barrel length with the ammo you’re using. Calculate those drops in MOA against the MOA drops provided by Sig. It likely still won’t line up but might get you close.

If you’re looking for a single source that will be a good guide for ballistics, intro distance shooting, reticles, and using the tools you own, I would recommend purchasing:

The Long Range Shooting Handbook by Ryan Cleckner.


It will give you years worth of resources and learning material for $20 on Amazon.

The charts will get you close,  but really there is no substitute for putting rounds down range and recording your data.  Everything will always vary some. Use a range finder for accurate distance measurements. Practice estimation, then verify,  you will get good in no time.

I typically zero off a 10 shot average. New rifles I run 200-300 rounds or so down the tube before dialing in my zero on a given load.  Bore sights have always been a non-necessity in my opinion,  literally look thru the tube,  adjust if needed.

I would just say (for you general information) that there is really no single "best zero distance" for all scopes and firearms.

The distance you use to zero your scope depends on things like what ammo you plan to use, the length of barrel, what typical distances you expect to be working with and what you are going to use the rifle for. For example, a rifle used for hunting in the woods where you'd rarely get a shot much beyond 100 yards would probably be better looking at maybe a 50 yard zero. For punching targets at 300 yards you're going to be looking at specific bullet weights and loadings than hunting and so your zero is going to be perhaps 200.

Set up your scope according to what you plan to do with it and what ammo your are going to be mainly using.  As far as getting preliminary zero (on target at ~20 yards) just pull the BCG out and sight through the bore and the scope. Adjust the scope so the cross hair zero is roughly 1" above the bore zero.

Yep, it is rather useless, even with a zero of 100 yds.  Correct me if I am wrong here but using std 556 ammo 55 gr ballistic (assuming a 20" barrel) from Federal shown the first BDC hash of 5.04 MOA correlated to somewhere around 375 yds!
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So OP, if you want to keep it simple, assuming the published data from Federal is useable meaning your barrel is 20", zero at 200 yds would be your best bet IMO.  Put the POI at -2.5" below point of aim, from 50 yds out to 250 yds, aim dead on, and the 1st BDC hash mark would correspond to 400 yds.
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Yeah, Sig manuals are typically useless for figuring out the reticle.

OP, you’re going to find yourself shooting and confirming.  

For books: Understanding Firearms Ballistics, to start. The cover is black and red. If you want to nerd out with pencils or dry erase, that’s the primer. Then anything by Zediker or Litz. Especially Litz. These books will give you a background of knowledge, but not solve your current problem, which is lack of reticle info.

Strelok Pro is usually the go to app, but I can’t get it anymore.


Edit, looking at the reticle diagram above, with a 16” bbl, you can probably zero it at 50 or 200, then the first stadia would be 400, second one 500, etc. Its not exact, but fairly close. Worth a try. The key to using BDCs is usually to true them up for elevation at the longest distance you use them.

I can tell you a simple method, others may or may not agree on it being the “right” method.
Your scope adjustments are 0.5 MOA per click, i would zero at 50 and confirm at 200
With that setup, inches=clicks which makes adjustments easy.
In my anecdotal experience using an ACOG and primary arms LPVOs the bdcs will be close enough for use on human size targets. If you are trying to hit x rings, i would adjust for the range and conditions you are in at the time.

You can still download it through Samsung App Store.

There's no need for strelok specifically. If you know your velocity and environmental conditions, you can use any ballistic app, and adjust your zero to best match your needs.

Remember to confirm drops AT DISTANCE.

One nice thing about Strelok is that it has most of the reticles so the subtensions are there.  If you don't have access to the longest distance on your hash drops to confirm, you'll have to depend on your ballistic data and the app.

You either know your subtensions or you (own a primary arms acss bdc reticle) don't.

Without confirming at distance, you don't really know what you don't know.

Strelok has table view so you could look down the list and match up your subtensions or you could just use the reticle view. I like the reticle view.

When I was living in WA, our longest rifle range was 500 yards and my 3GR reticle goes out to 700.  When I shot hard as hell, there was a 710y bonus target which I was stoked to hit even though I never confirmed out that far but Strelok was accurate.

Let me try again, both a generic ballistic app and strelok do the same thing, with strelok showing you specific drops for your optic's specific subtensions on a screen whereas the rest give you a chart and you have to use your brain to match that to your subtensions or visa versa.

They're the same thing, only the view is different.

Edited to add: you can even break the ballistic chart down to 5 yard increments with geoballistics as an example.

Yes that’s right, depends on whether you want to see it on a table or with your reticle.

Some are visual learners vs other methods, and Strelok has been a good tool. And sometimes manufacturer’s manuals don’t include adequate subtension (sp?) or target-relative info, which Strelok helps with.

Attached File

That's not going to do anything to change the subtensions on that garbage reticle.



The whole point of a BDC reticle is that you're not making adjustments to the elevation turret.




Using a 200 yard zero with that SIG reticle, the first subtension will produce a point of impact at 394 yards.  That's garbage.


This is what a simple, functional and effective BDC reticle for a LPVO looks like.

The bullet-drop compensating reticle on the Trijicon Credo HX is based on the German #4 reticle.  The Credo HX reticle has four stadia lines on the horizontal cross-hair for rudimentary windage and moving-lead hold-offs.  The vertical cross-hair has five stadia lines to compensate for bullet-drops from 300 to 700 yards.







The come-ups of the BDC reticle are a practically perfect match for my 55 grain loads.







A rough check at 50 yards of the BDC come-ups shows that they are just as advertised.  Obviously, since this is a second focal plane reticle, those particular bullet drop compensations only apply with the magnification set a 6X.










....

.5 moa clicks at 100 yards are not 1 moa clicks at 50 yards, they'd be .25moa clicks. .5 moa clicks would be 1 moa clicks at 200 yards. See people mess this up all the time.


Edited to add: this is meant for the thread's op, DWPW, not as an attack against etslick

I just noticed OP's stick is a 10.5" barrel, so rough muzzle velocity of 556 would be in the neighborhood of 2500 fps.  The suggested 200 yds zero is still valid but the first hash mark would be 325 yds using Fed Ballistic.

OP needs to understand ballistic if you want to learn how to make any BDC works for you. The 2 key variables are muzzle velocity and bullet weight, the other part of the equation is your sight height, center of scope to center of bore (FYI most likely range of any AR scope set up = 2.5-3") . https://www.federalpremium.com/ballistics-calculator

For future references, look up the scope's reticle and its substensions first before committing to the purchase.  As you can see in this exercise, that Sig reticle might look cool with all those lines and dots, but they don't fit your particular weapon/application.

What? No. MOA is an angular measurement, not an absolute measurement of size.. Half a MOA is half a MOA, regardless of range. How much movement that represents is what changes with range, but it's a fixed ratio of movement-to-distance.

0.5MOA at 100yd is 0.5 x 1.047 inches, which works out to 0.5235 inches. Half that width (call it about 0.2618) at 50yd, and a quarter of that (right about 0.13) at 25. But it's still a half-MOA.

Bore Sighting:

Pull the upper off the gun. Pull the bolt carrier from the upper. Place the upper on sandbags and be sure the upper/scope is level and the whole upper is rock solid on the bags pointed at a high contrast target. Look through the bore from behind the gun until your barrel is pointed at a high contrast target. The point the barrel is aiming at should be perfectly centered while looking perfectly straight down the bore not touching the upper at all.

Now, without touching anything, look through the scope and see which way you need to adjust the  turrets. Do one adjustment at a time and repeat the process. Dont worry about direction or clicks. Give the turrets a half a revolution at a time and it will be obvious which way to turn and tbe slow to quaerter turns and individual clicks once you are clise.

Adjustment of the scope/upper/barrel will have moved once you touch it to adjust turrets, so re-zero with the bore on bags until the barrel is pointed at a high contrast target again AND IS STILL AIMED PERFECTLY WITHOUT YOU TOUCHING IT, then lift your head and check the scope's view WITHOUT TOUCHING the upper. Once the bore and scope appear perfectly zeroed to each other,  both aimed at the exact same spit as best as you can see, you have a bore zero and WILL be on paper at 50 yards on the first shot.

This initial high contrast target for bore zero does not need to be an actual target. Since things look distorted looking down the barrel,  I prefer a bright, high contrast, right angle corner to look for such as a corner of a bright square number sign over the target or even a window of a building if not at the range. Take your time here and you save a lot of headaches at the range not hitting paper and guessing where to aim and dial.

Actual zero:

Fire a round at the target at 50 yards using carefull aim. Use a target of no more than 2" in size as your bullseye. Fire another round at the target. Both rounds will land on paper. If the two rounds are less than an inch apart, use the spot between them as your current point of aim. If not, fire a third round and use the center of the group as your scope's current aiming point.

Look at the turrets on your scope. There will be a direction arrow for turning labeled UP on the top turret and RIGHT on the side turret. These are the directions you want the BULLET IMPACTS/GROUP to move on the PAPER TARGET, not the direction you want the reticle to move, which will be the OPPOSITE direction your were dialing for a bore zero.

ONLY ADJUST ONE TURRET AT A TIME if you are new to scopes.

Once you get within 3" of the bullseye, start shooting 5 round groups and use the center of the group to guide you. Try to shoot as small a d consistent a group as possible. Don't be in a hurry.

Once you can hit back to back shots inside a 2" circle at 50 yards, you are done. Move to 100 yards.

At 100 yards, you will probably be hitting about 1-3" high. That is normal. Shoot at smaller 1" bullseye targets. Zero the windage first. Then zero elevation. Move the turrets one click for each 1/4" you want the bullet group to move if MOA turrets, 1/3" if MIL turrets. This will be correct, half what you need or twice what you need at either range.

Duty Load / Self Defense Load / Target Ammo:

Once you are zeroed with FMJ at 100 yards, rezero with your chosen self defense load at 100 yards. With your chosen self defense load, your bullets will be landing at a different spot than FMJ. Don't worry about that. Zero the defensive load. This target or duty ammo group size will be better/smaller than your FMJ load and likely produce groups half the size of your FMJ ammo.

Zero the rifle with the self defense load at 100 yards for both elevation and windage using 3 round groups if all 3 bullets are within an inch, or 5 round groups if all bullets are within 2 inches, but over an inch at 100 yards. If groups are over 2 inches at 100 yards, something is wrong. Shoot another group. If group sizes are over 3" have someone else shoot your duty ammo and see if they are shooting under 3" groups. 99% of the time they will shoot under 3" groups. If over, your ammo sucks, your barrel sucks, your optic is broken, or your scope/mount is loose. Shoot some Federal Gold Medal Match ammo at 100 yards.if it also shoots over 3" at 100 yards for you and another shooter, the problem is the optic or mount.

Once you are zeroed with duty ammo at 100 yards, you are done unless you want a 50 yard zero. In that case, move back to 50 yards and shoot at a 1" target. You will not adjust the windage. Your bullet will land low on target. Shoot 3 round groups. Dial up until at least 2 of the 3 bullets in your group land within the 1" target. You are done.

Number of clicks per distance. For 1/4 MOA scopes, you will move the group about 1/4 inch per click at 100 yards. For 0.1 MIL scopes, you will move the group about 1/3 an inch at 100 yards. At either range, just dial 1/4 inch for MOA or 1/3 inch at 100 yards.  Some LPVOs have 1/2 MOA adjustments or 0.2 MIL adjustments. This will make the 1/4" or 1/3" per click right at 50 yards. Otherwise 1/4" for MOA or 1/3" for MIL is right at 100 yards.

Either way, if you just use 1/4" per click or 1/3" per click you will either be correct, need twice the adjustment, or need half the adjustment and it will be self evident when zeroing one turret at a time. I never even look at the adjustment of someone else's optic when I zero it because frankly, it does not matter. Either way you should get zeroed in a 20 round box of ammo.

LASER bore sighter:

This is to get you bore sighted at an indoor range. You put the laser bore sighter in your chamber and it projects a laser on your target through the barrel. Same concept as just looking down the barrel. Dial the scope's adjustments at 15 yards until the scope aligns with the laser for windage perfectly and the dot is about 1-2" under your point of aim with the scope's reticle. Now you will be on paper at 50 yards. It is NOT a precision zero, it is just to get on paper. You can't really see the laser dot worth a crap at 50 yards or 100 yards outside, during the day. It is just a close range, crude, indoor zero for when you don't have a bench and sand bags.

For the reticle substentions, you use max magnification and can use a ballistic app to give approximations, but you need to shoot KNOWN distances with YOUR duty/self defense/target load to see where they ACTUALLY hit with YOUR rifle in YOUR location. Apps are never perfect. You will need a long range target camera system or acoustic target system to shoot past 300 yards. Spotting scopes don't work for paper targets past 300 yards. Steel targets can be of crude assistance at ranges of 400-600 yards if they are repainted each 5 round group. This is just some reality for you to consider.

The only difference between what you posted and what i posted is that you're referring to the physical click movement measurements of the turrets and I'm referring to the affect each click has on point of impact at distances other than 100 yards. We're both saying the same thing.

I wasn’t planning on getting pedantic; I understood what you meant. But to be technically correct, you’d have to sub in “inches” for “moa” in a few spots in your post.

Edited: nevermind, I'm washing my hands of this.

Thank you VERY MUCH @Bravofivetwo, @molon, @DevL

I REALLY appreciate all this info. I'm gonna check out the SIG TANGO MSR 1-6 but once I have some of the basics down, especially the use of the BDC reticle, I will probably try and hunt down something in the $800 - $100 range in a 1-8 with an MOA reticle.