MRAD v MOA rifle scope

[Jacklurcher]

I've never understood why scopes have mildot reticles and MOA turrets. I used to think there was a MOA turret mountain somewhere that manufacturers were using up before starting on MRAD turrets.

You end up with something like a 3-9 SFP Hawke scope with a mildot reticle that they claim to be correct at x 10 magnification (is it half mildot at x5?) with MOA turrets. Fortunately I was born in 1966 so I'm used to mixing metric and Imperial units.

MOA turrets are a bit more precise on zeroing as 1/4 MOA is a smaller angular adjustment than 0.1 MRAD, which is probably better for airguns which tend to be used on small targets at very close range.

MRAD is better for human sized targets at distances of hundreds of metres or correcting artillery fire at kilometres.

Still seems strange to mix the two on a single scope though.

[Travis299]

Having just had the FFP/SFP thread which went quite well, I feel we are probably ready for the "big one", MRAD or MOA
and frankly do people actually have a clue what they're doing ?

MOA
Most of our scopes will be using 1/4 moa turrets, so 1 click will change the POA by 1/4" at 100yds or 1/8" at 50yds, 1/16" at 25yds
Equally at 200yds 1 click is 1/2" or at 400yds is 1"

MRAD
MRAD turrets are 1 click = 1/10th mil, so change 1cm at 100m, 5mm at 50m, 2.5mm at 25m.
or 2cm at 200m, 4cm at 400m

Many, if not most scopes currently sold have a "mil-dot" ret of some type, yet the vast majority of UK airgun scopes still use MOA turrets which adjust on a completely different scale
Surely if your scope has mil-dots, to use them you need the turret adjustment that can match, otherwise they're just random marks.

And this is also where the FFP (MRAD) scope really wins because the mil-dots are always true (at any mag) so if POI is 2 dots out you know 20 clicks, 1.5 dots out 15 clicks, etc.

This may help.

One MOA Calculation (Note, MOA = minute of angle).
This is how you can determine the one MOA for any target.
1. Determine the distance or range to this target.
2. Convert this number to inches or centimeters for metric.
3. Double this number. (Diameter of a circle at this target distance or range).
4. Use Pi, 3.14159265 times the number in step 3. (Circumference of a circle is Pi x D).
5. Divide this number by 21,600. (Note 21,600 is the number of minutes in a circle, 360 degrees times 60 minutes in one degree).
This number is the one MOA in inches, or centimeters if used, for this distance or range to the target. (Group shots are measured center to center).
Example:
1. 100 yards to target.
2. 100 times 3’ times 12” equal 3600” to the 100 yard target.
3. 3600” x 2 equal 7200”. (Diameter of 100 yard circle in inches).
4. Pi 3.14159 times 7200” equal 22,619.448”. (Circumference of 100 yard circle).
5. 22,619.448” divided by 21,600 = 1.04719”. (One MOA at 100 yards in inches).
This number is usually rounded to 1” for one MOA at 100 yards. The one MOA equal 1” is an ARC measurement and not a straight line as it is a very small section, 1” of the overall circle circumference at 100 yards.
A trivia note, one MOA on the moon is about 69.5 miles, 111.85 Kilometers! (238,900 miles, 384,472.28 Kilometers to the moon).

Also:

Milliradians, (MRAD or Mil) and Minute of Angle, (MOA) Trivia MOA vs MRAD Reticles | An Official Journal Of The NRA (shootingillustrated.com)
(Best with a 6 pack of Beer)

Formula for circumference of a circle = Diameter, (D) x Pi, (Pi = 3.14159.)
There are 7200” in (D) diameter of a 100 yard circle. (100 x 36” x 2 = 7200”)
Circumference of a circle at 100 yards = 22,619.448”, (7200” x 3.14159 Pi.)
1 MRAD & 1 MOA is an angular numeric calculation at a specific distance or range to the target. Shots are measured center to center.
6,283.185 Milliradians (MRAD) = 1 CIRCLE (Pi 3.14159 x 2 x 1000 = 6,283.185, mathematical.)
6,400 Milliradians = 1 CIRCLE, (NATO rounded MRAD.)
21,600 Minutes = 1 CIRCLE, (360 degrees x 60 Minutes in 1 degree = 21,600 minutes)
1 MOA = 1.0471975” at 100 yards, 22,619.448”/21,600 Minutes, (1” rounded.)
1 MRAD = 3.6” at 100 yards, 22,619.448”/6283.185 MRAD, mathematical.
1 MRAD = 3.534” at 100 yards, 22,619.448/6400 MRAD, NATO.
1 MRAD = 10 cm at 100 meters. (2 x PI x 1000 = 6283.185 MRADs in a circle). 100 meters = 10,000 cm x 2 = 20,000 cm in diameter of 100 meter circle. 20K x PI = 62,831.85/6,283.18 MRADs = 10 cm; for (1 MRAD at 100 meters = 10 centimeters).
Scope settings MOA or MRAD.
It also depends on what your scope's notion of 1 milliradian is, because the NATO milliradian differs from the mathematical definition of a milliradian.

A mathematically accurate radian is that part of a circle where 2 * PI radians is a full circle, and a milliradian, (MRAD), is 1/1000th of a radian, so a full circle is equal to approximately 6283.185 milliradians (2000 * PI).
But the NATO definition of a milliradian for use in ballistics is that a full circle is split into 6400 NATO milliradians.

Anyway, the difference is not very large, with mathematically accurate MRADs, 1 MRAD is 100 cm @ 1000 m, with 1 NATO MRAD, it is 98.2 cm @ 1000 m. For this reason, if your scope uses mathematically accurate MRADs, 1 MRAD is about 3.44 MOAs, but if it uses NATO MRADs, then 1 MRAD is 3.375 MOAs.
 
The distance of the reticle's movement per click is tan(angle) * distance, however, at longer distances this is not exactly equal to the change in point of impact, because of the difference between changes to the line of sight and changes in the bullet's trajectory.

degrees = MOAs / 60
MOAs = degrees * 60

degrees = MRADs / (PI * 1000) * 180
degrees = (MRADs / 6400) * 360 [with NATO MRADs]
MRADs = (degrees / 180) * PI * 1000
MRADs = (degrees / 360) * 6400 [with NATO MRADs]

MOAs = MRADs / (PI * 1000) * 10800
MOAs = (MRADs / 6400) * 21600 [with NATO MRADs]
MRADs = (MOAs / 10800) * PI * 1000
MRADs = (MOAs / 21600) * 6400 [with NATO MRADs]

[angrybear]

Thanks for making the effort, but TBH I deliberately didn't bother to put the maths to avoid confusion.
the shooter only needs to know the effect on POA, not the theory of where they come from.

[Muskett]

Nothing wrong with understanding the theory of the Maths involved. Thankfully, ballistic calculators can do it all super fast. The more advanced calculate in all the variables too.
I still maintain that even putting in the best data possible to run such programmes they can only get you close. Only doing the real practical will give proof of spot on, and remember every day has different conditions.
Ballistic calculators can usually do both MOA and MRAD; just don't go mixing them up with your reticule and turrets.

Though I'm not the greatest fan of Hurus reticule system, they did champion FFS for extended range use. For long range use then the FFP systems has a lot of merit.

BTW, I like using meters over yards. Your laser and drop charts need to know.

Thankfully too, keep your hunting to "point blank" ranges doesn't require too much ballistic input. However, some effort is required to find a perfect zero range where the projectiles flight stays within "kill zone" parameters.
I find a couple of drop point references can extend the "point blank" to be a little longer and a little more precise. If I want more then dial and use any added aid to hand. All from doing the practical and taking notes.

[Muskett]

Last point, if I was new to the game I would use meters and MRAD. Stick to them only.
6" is is 15cm Its how you use it.

[harvey_s]

Does any of this make any difference to any airgun shooter?
Somehow I very much doubt it and most just know their combo and use the "random hash marks" without any concerns over their calibration.
I also suspect that the reticle shape, size and configuration means more to the shooter than whether it's MOA or MRAD.

[Muskett]

Correct, because most air rifle shooters buy their kit first and then work out how best to get it all to work on their plinking grounds. Much buying decision done by shop recommendation, a "package", and to fit a certain budget. Later they might "go advanced". But then plenty here are stuck in the wool old farts like me.

I think side parallax to air rifle ranges is the big feature over much more than just an "adequate" scope.
FT and HFT have their own "scope" rules.

Probably the most "advanced" scope for air rifle use is 3-12 Digital Zulu, which has all the features including ballistic calculator and aim adjusted point. Not your traditional "glass" though. Has anyone set one up correctly and done a full FT/HFT course; was it a help?

[gsxrman]

Does any of this make any difference to any airgun shooter?
Somehow I very much doubt it and most just know their combo and use the "random hash marks" without any concerns over their calibration.
I also suspect that the reticle shape, size and configuration means more to the shooter than whether it's MOA or MRAD.

It probably doesn't make that much difference to any shooter who tests and pre determines impact points at different ranges. If you were working it out on the fly then to me MRAD be easier. Dialing in a turret doesn't matter (MOA?MRAD) if you have list of settings for given ranges i.e. FT style.

[gsxrman]

Nothing wrong with understanding the theory of the Maths involved. Thankfully, ballistic calculators can do it all super fast. The more advanced calculate in all the variables too.
I still maintain that even putting in the best data possible to run such programmes they can only get you close. Only doing the real practical will give proof of spot on, and remember every day has different conditions.
Ballistic calculators can usually do both MOA and MRAD; just don't go mixing them up with your reticule and turrets.

Though I'm not the greatest fan of Hurus reticule system, they did champion FFS for extended range use. For long range use then the FFP systems has a lot of merit.

BTW, I like using meters over yards. Your laser and drop charts need to know.

Thankfully too, keep your hunting to "point blank" ranges doesn't require too much ballistic input. However, some effort is required to find a perfect zero range where the projectiles flight stays within "kill zone" parameters.
I find a couple of drop point references can extend the "point blank" to be a little longer and a little more precise. If I want more then dial and use any added aid to hand. All from doing the practical and taking notes.

Depends on your set up, but I have a PBR of 9.2-42.3 Yards

[Muskett]

There is a lot to commend knowing your PBR ballistic curve for your calibre and its velocity. 1" is generally considered the air rifle kill zone. Somewhere on the trajectory curve the closest will 1/2" low, in the middles 1/2" high, and at the furthest 1/2" low again. There will be two places where it's spot on; on zero perfect. For each combo exactly where the zeros are needs to be worked out by doing the range practical as no two combos are exactly the same. Heck even the 1/2" can be improved on when making the shot as the target is "on the close side", "between the zeros", and "at the furthest". A clear crisp glass scope with a good plex can give enough quality sight picture to do "perfect" shot placement; just takes a load of practice and getting familiar with it all.
Change ammo, and ammo weight, then it needs working out again. Taking notes helps keep track of results.

So MAO or MRAD, SSP or SFP, really isn't so big a deal if shooting to PBR. As I said KISS.
John Darling would stalk to his PBR zeros to put it in the bag.

Note, 12ft/lbs air rifle pellets have no concern-able shock power to them, so perfect shot placement is everything. .22LR, .177HMR. and full bore calibres, have real shock, 3" to 6" of devastation; which is an aid to what constitutes their PBR.

However, there is a lot of fun to be had trying different systems on the target range. It's more shooting, pushing boundaries, and having some fun.

[angrybear]

Does any of this make any difference to any airgun shooter?
Somehow I very much doubt it and most just know their combo and use the "random hash marks" without any concerns over their calibration.
I also suspect that the reticle shape, size and configuration means more to the shooter than whether it's MOA or MRAD.

Well the first obvious thing is if you know, you can use the mil-dots to range prey in the field.
the second obvious thing is if you don't know which it is, you can't zero because your number of clicks will not put POI where you need it.

[harvey_s]

Well the first obvious thing is if you know, you can use the mil-dots to range prey in the field.
the second obvious thing is if you don't know which it is, you can't zero because your number of clicks will not put POI where you need it.

I think most airgun hunters can fairly accurately range their prey by sight and apparent size far easier and just as accurately as using mil-dots!
Equally regardless of the calibration between indices, after a reasonably short time they will get to know their reticle/mag combo well enough to estimate with the reticle they have.

The same applies to zeroing... it's not rocket science - any follow up movements will just be a simple multiplication or division of the error.

[Muskett]

This^
For those shooting beyond PBR, then there are always laser rangefinders or use a high mag scope's parallax and marked big wheel. Air rifle shooters are pretty capable lot once into the hobby of it all.

[angrybear]

The same applies to zeroing... it's not rocket science - any follow up movements will just be a simple multiplication or division of the error.

I was speaking with voice of experience

I was trying to zero a .17 rimfire at 100yds and going round in circles, measuring the centre of group, adjusting & going to far.
Being a scope I'd pulled from the cupboard I was certain it was MOA but admit hadn't checked & sure enough when I actually looked it was MRAD,
went back to make it 100m, & using 1/10 MRAD per click put it dead centre with the next group.

Being so used to 1/4 MOA clicks I've done it more than once (the FAC air is also MRAD) but now I realise after the first adjustment.