Translating MOA to clicks on your scope

[Kikn]

Just trying to learn and thought I'd post this and see if I'm on the right track with my thought processes.

Information truths

1. Barrel Length 16"
2. Yards and Path are for the Harnady 129 gr. SST (Provided from AA website)http://alexanderarms.com/images/pdfs...ballistics.pdf

3. Scope is configured for 1/4 MOA adjustment

<Formula used = path/yards=MOA>
<MOA * 4 (Scope adjustment in 1/4 MOA)= desired clicks necessary to hit target>

For now lets forget about the fact that 1 MOA really equals 1.047" and not 1" even as that is not part of this calculation just for simplicity matters.

(MOA is set to nearest tenth some numbers were very long)
Also note that clicks were either adjusted up or down one way or another due to the fact that you can't have .x clicks

Yards Path MOA Clicks
50 10.11 20.22 -81
100 21.47 21.47 -86
150 30.93 20.62 -83
200 38.35 19.17 -77
250 43.55 17.42 -70
300 46.36 15.45 -62
350 46.56 13.3 -53
400 43.94 10.98 -44
450 38.25 8.5 -34
500 29.23 5.84 -23
550 16.59 3.01 -12
600 0 0 0
650 -20.87 -3.21 13
700 -46.4 -6.62 -27
750 -76.97 -10.26 -41
800 -113 -14.12 -57
850 -154.9 -18.22 -73
900 -203.12 -22.56 -90
950 -258.07 -27.16 -109
1000 -320.18 -32.01 -128

[LRRPF52]

Your click values are shown for a 600yd zero. What is your question?

I never use that zero, by the way...temp shifts will screw you over big time, whereas a 100yd zero in 50 degrees will be the same at 90 degrees. Not so with a 600yd, I can promise.

I also prefer zero-stop scopes for my 100yd zero, where I index the turret at, then dial for the drop at different ranges. For a 600yd zero, most of your shots will be a negative dial, since most distances will be under 600. With a 1/4 MOA scope, you'll get lost in the turn real quick.

Do you have a scope with 1/4 MOA clicks for elevation?

[Kikn]

Your click values are shown for a 600yd zero. What is your question?

Ok, you kind of picked up on what my question really is that I didn't express in my first post. What I am trying to figure out is how I can take the above data and make it usefull. (Granted I understand that it is not going to be perfect; but ball park close would be nice +/- 12" at least puts you on paper right? So then I could fine tune and come up with a cheat sheet of sorts, for quick reference) So using this data with my scope set to a 100 yard zero. Would it then be plausible to think that I could just subtract the 21.47" from the remaining cells in the yardage collum then do the math again to get my MOA and then figure out how many clicks that is?


Do you have a scope with 1/4 MOA clicks for elevation? Yes, my scope is 1/4 MOA


Also I don't know about a lot of you guys but I don't have the equipment/time/money to come up with this kind of detailed information in the data provided by AA.

[LRRPF52]

You need to know what your actual carbine's muzzle velocity is first, then run the numbers through a free on-line ballistics program. I use Berger's a lot since it's simple.

You need your MV with that load, the BC data of the bullet, your optic height above bore, and your environmental conditions, with temperature being the most important. Run those through a ballistics program, and set the output units for MOA. You will have to multiply your MOA drop data by 4 to get your click values. A lot of programs have those options for you, (to enter in scope turret click values).

Once you have your data, put it into usable click value form, since nobody will be dialing 10.98 MOA, for example. That is 11 MOA, or 44 clicks with a 1/4 MOA scope.

Anyway, most guys have a small card with the range column on the left, their elevation correction for that range next to each range increment, and wind correction at that range for a 10 mph full-value wind. You can tweak your wind data to the conditions since windage is a linear function, not like elevation trajectory.

So you have a little card attached to the stock or hanging from your scope mount that you can reference. You're at a known-distance range, or have lased a target at 400 yds. Let's just say your elevation correction next to 400 yds on your card is "11 MOA" or "44 clicks" on your 1/4 MOA click scope. You will dial your elevation turret 44 clicks, which moves your reticle 11 MOA lower in the FOV if you were able to watch it in a vice. The barrel will now be oriented higher in order to lob the projectile in a path that will intersect the target at 400yds.

If you have a full value wind with wind direction blowing from right to left, your barrel needs to point into the wind to compensate. Let's say the wind is 10mph for simplicity, and your data says you need 3 MOA of windage to compensate for that wind speed at 400yds. You will crank your windage knob so that the reticle moves with the wind, or to the left, which points your barrel more to the right.

Now you take the shot and should be dead on, provided the conditions didn't change. If the wind shifts direction and is now coming from over your right shoulder and blowing to your left over your left shoulder, it is a half value wind, and you cut your windage correction in half down to 1.5 MOA, or 6 clicks with your 1/4 MOA turrets.

That 129gr SST is a big pill to push for a 16" Grendel. I would recommend staying with the 123gr bullets and under, but you'll still be effective for hunting within 200yds I'm guessing.

Now you see why a lot of guys like Mils more and more, since it is all based on 10, with .1 Mil click values, and a Mil reticle to match. You will also find out really quick why a zero-stop is pretty much a must, unless you mark your scope turret with a paint pen to indicate where your zero is.

The fastest method I've found so far is custom BDC decals for your load and turrets:

[LRRPF52]

Here's a great article on this as well:

http://bulletin.accurateshooter.com/2009/05/print-and-laminate-a-ballistics-data-card/

[Kikn]

Thanks for the info it is really good. BTW: I don't plan on shooting anything over 123gr bullets. I was only using that diagram as a reference for my inquiries.


What you are referring to is what I am trying to get done or at least figure out to a more competent degree.

I'm mostly interested in the math part of figuring this out, even though I do appreciate the ease of using apps to do mundane configurations so basically my math is right, provided the ballistics information I am using is correct and/or bullet flight path. It’s hard for me to accept that a program written by someone will be adequate enough to overrule documented results on paper, which is why I was using the ballistics information from AA.

But perhaps you are right and there is no sense in trying to reinvent the wheel when regardless it will still be round at the end of the day  . But at the end of the day, in our automated world, I do realize it is important that we still know how to make the wheel, less we become consumed by ignorance and dependent on other inanimate objects to do our bidding. Then will we know that the information being provided is in fact true and accurate to some degree.

(Pardon the senseless rant about technology, I do work with computers and I see first-hand how people are dependent on things they don’t understand, yet have no desire to learn so that they can control the machines instead of doing what the machine directs them to do)

I do like the idea of having the color coded turret for the different bullet types/loads for an easy zero for that type configuration. Is that something that you made or did you buy it?

[LRRPF52]

A friend in Finland did it. There are three different wind speed tracks if you look at the windage knob. My wife and my father can calculate the drag models for a regressive projectile being affected by gravity, wind resistance, and aerodynamic BC, but I can't yet.

My dad's wireless keyboard went tits up on him earlier this year, so he started crunching numbers on his old note pad. He figured calculating the orbital trajectory of the moon would be nice. I said he should take the keyboard from another computer and plug it into his, but that was too much of a task in the real world for him I guess. After a while, he figured the moon's orbit was somewhere over 800m/s, and we concluded that if the moon was perfectly spherical, you could shoot yourself in the back with a .270 Winchester.

He went off to another room, and I wondered if he had over-looked something, so I checked the batteries in the wireless keyboard...he had inserted them backwards! I gave him a real hard time after that one.

"Hey Einstein! You put the batteries in backwards!"

"No I didn't...did I?"

[Rambozo]

What's with counting clicks? Are your turrets not marked in minutes? This whole counting clicks thing seems to be more work than necessary.

[LRRPF52]

I hope nobody is counting clicks. I just watch the click value increments on the turret, and blow through them quickly. This is also where a quality scope with positive and repeatable click values come into their element, since you can't afford for the gears to slip in rapid turning. There are very few scopes that do this reliably.

[Rambozo]

Well yeah, that's what the turrets are marked for, right? I hope he isn't struggling with the coin type. That wouldn't be any fun.

[Kikn]

LoL...no I'm not that dense. I just wanted to put things in the simplest of forms which is a single click or 1/4 MOA per click (just for those that would be counting.

Speaking of batteries. I had two individuals send me their laptops yesterday because they would not power on. First question I asked did you charge the batteries and did you try powering it on using only the A/C adapter. Response, "Yes, they just won't turn on". I get the systems in yesterday and low and behold the batteries are dead, the plugged in the A/C adapters to an outlet and to my amazement the systems powered on and i proceded to run a diagnostic on the system which is passed and charged the batteries.... I guess they though they could run on kinetic energy somehow o_0 or possibly even a photocell that isn't attached, (Not exactly a Ti calculator)

[vanguard138]

KILN

I am not sure they teach multiplication tables anymore in school.

[Kikn]

KILN

I am not sure they teach multiplication tables anymore in school.

Yeah, they just pass out calculators with AMD proccessors (wasn't to many years ago AMD had an issue with its MATH coproccessor and not being able to do math calculations correctly)

Another thing my mom informed me of that they stopped teaching in some schools was how to write in cursive. She has a boss that works at Zales corp that has a masters degree but can't even spell her own name (Except in printed form) also her god daughter who is now in college was never taught in school how to write in cursive.... I was astounded.

[Mutt]

With the coin type adjustments, I'd just use the ballistic calculator on my droid phone and just use the holdover it shows me ...... LOL.

LRRPF52 ...... do you happen to have a link for that ballistic calculator you are using???

[LRRPF52]

http://www.bergerbullets.com/Ballistics%20Program/index.html

Very easy to use. Just pay close attention to how you enter G1 and G7 BC's, as well as your optic height. You can play around with the output units, but I use MILs since my optics are in MILs, but it has MOA, inches, etc.