Home Forums Hunting & Shooting Long Range Hunting Come up inches/MOA

Someone please explain this to me:

Looking at the ballistics calculations for 300 Win Mag, I get "Come up 9 MOA" or so, I watched this youtube video which basically said take 9 and multiply it by 4 (1/4 inch clicks) so at that distance come up 36 clicks, Does that sound correct?

Thanks for someone that can explain this simply to me,

Moa measurement is slightly different than inch.
Try to convert your moa to inches. If you use jbm, you can change the first line to inches.

Putting aside technicalities about mixing units for angles and distances, 1 MOA is about 1" at 100 yards.

So 9 MOA would be about 9" at 100 yards. Assuming "1/4 inch clicks" means 1/4" at 100 yards, we'd need 4 for each inch, 9 inches worth, and that's where the 4 times 9 equals 36 clicks comes from.

What we've done is approximated the clicks as 1/4 MOA each. Or 4 clicks per MOA. If we stick with that then we can forget about inches at whatever distance and such.

For example, a mild 308 target load needs about 5 MOA from a 100 yard zero to be on at 300. So 5 MOA times 4 clicks/MOA = 20 clicks.

Forget clicks and just dial to the number 9 on your turret.

Exactly.....

And on JBM, put MOA on the first and second lines, so you don't ever have to look at inches......

While good information if you want mindless robot like movement "turn to table value"... But wouldn't it be easier to learn & know what your actually doing?

If you really are interested in playing in the dope range, spend the time to learn what going on & it will help greatly.

MOA (or mil-radian if your metric) is an angle. That angle translates into a measurement at a certain distance. The farther the distance away, the larger that measurement (think "similar triangles" if you can remember back to 9th grade geometry class). Having a good knowledge of this correlation will really help corrections needed & getting dialed in.

Example:
First shot of the day calls for 800 yards. Dope sheet (Ballistic program, previous check, wherever you get the value) says come up 15.25 MOA. I dial to that (yeah don't count the clicks but make sure you have solid zero), just dial to the 15, then 1/4 way to the 16. Then if you pull the trigger & your 6 inches low because conditions have changed that day. Well, there is two choices, you can hold over 6" and make the hit or dial up what would correlate closest to 6" and hold center. If only shooting 1 distance hold over is just as good but if your turning to shoot 875 yards right after, that MOA trurret correction at 800 would be very valuable (because your not going to be the same 6" low at 875; it will be more, an angular similarity to the 800 though).

Knowing 6" at 800 yards correlates to ~.75 MOA, 6/8 for quick math (however its actually .72 MOA, 6/8.378). Make that 3/4 (.75) MOA correction, hit center, then you can add that (extra .75 MOA) for called value at 875 & you'll be DAMN close if not center. Carry that info into your next range (say 640 yards) and your golden instead of being off all day.

It may sound complected at first but it's really simple (simple enough to make rounded math figures in your head afield for very close corrections) with just a little effort on your part. Plenty of info on the net out there to learn from.

You can even divide too and don't need 'JBM' to work things out, but you will need to shoot to verify.

If you're 20 inches low at 400 then all you need do is divide 20 by 4

If your reticle and turrets are in the same angular unit of measure (moa or mils), you don't need to bother with linear distances (other than range to target), and related math problems.

Measure first-shot error via the reticle, and apply correction via turrets or reticle hold-off.


Guessing linear distance at long range, and then using conversion math, only slows you down, adds a needless layer of complexity, and introduces opportunity for errors.

^Yep

I agree but there are very few scopes (until you get into the high end market) that offer a consistent stadia in angular measurement. Most are trinkets for estimated drop. I'll bet the OP doesn't have it.



Knowing the size of the target your using, one can make rather close estimations. If you don't have anything to reference but hairs. Simple math (usually small #s), especially in estimation, take little time. With a little practice it's way quicker than missing extra times.

Of course that ALL requires being able to spot your hits. Usually easier at the range (you've got all the time in the world) than while hunting (spotting hits in grassy/wooded/flat areas are more difficult, the live targets don't stand as still as paper or steel either).

Man.... there's a lot of folks out there who like to make this stuff WAY harder than it is.

Thinking in "clicks" and "angular measurements" is a sure-fire method for getting in your own way.

I hear you on "clicks" but minutes of angle and milliradians are measures of angle by definition.

They sure are... but when you think about them that way you get all messed up.

No need to ever think about the measurements involved in mil-rad..... simply use the reticle as a reference and dial the measured necessary adjustment.

Use the 1":100 yard ratio with MOA or IPH and do a little quick math....

Actual shooting makes this WAY easier... but there's not too many guys who actually shoot that can skullphuck this stuff to nearly the magnitude that couch-bound ballistic program jockeys can.

Matters little to me if a miss is a foot, a meter, or a 10 yards, I dial to the impact and shoot again.

There may be times one can't get "still" enough to hold back center of where you where aiming and dial to impact. If in awkward position it's a task to stay or (most likely) get back in the gun in time to see the impact. Much less set rifle in a set of sticks in the sitting position & stay still enough with one hand to dial with the other...


Works great on the bench though.



So without "thinking about them that way", how do you describe it to a shooter that doesn't know? Sounds like your doing it without thinking about it. But to describe it to someone who obviously has little to no knowledge of doping line of sight, "just do" it doesn't help much.

If one takes the time to understand the physics behind the system, they want get all messed up when they think about them. A calculator does a great job with crunching numbers. But knowing how to multiply, divide & estimate the number in your head would save your ass when something goes wrong/batteries go dead.

Not trying get in a back & forth with either. Just say'n, there's more than one way to skin a cat, especially when there are different cats & different knives. And why there are so many different preferences, opinions & choices.

If you can't see the impact, you can't hold or dial to the miss.....

Amazing thread and replies.





LOL

It'll be more awesome now that your here....

At least he's humble about it....