OT: "mrads" instead of "moa"

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Goat
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OT: "mrads" instead of "moa"

Post by Goat »

I did what I thought I would never do and bought an evil black rifle (surprisingly I have had no desires to shoot up shopping centers or college campuses.) Now the journey has begun to equip this contraption the way I want it. It is a 6.8mmSPC flat top with a 16" bbl from Stag arms. One of the things I wish to do is set it up with either one set of optics to do everything or with one set for things up close (less than 100yds) and another for things a little further out. I really don't expect to ever clear a house unless it is my own but also want to think about what "could happen." I am open to suggestions about either one set or two.
The real question is about Vortex Optics they use "mrads" to describe the substension of the reticles in their tactical scopes instead of moa measurements, what in the world are "mrads?"
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BobM
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Re: OT: "mrads" instead of "moa"

Post by BobM »

Milliradian. If I remember correctly one "mil" is 3.6" @ 100 yards, one meter at 1000 meters.
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AJMD429
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Re: OT: "mrads" instead of "moa"

Post by AJMD429 »

There are lots of ways to calibrate a scope - MOA, MilDot, Milliradians, etc. Some of the scope-makers have pages describing the conversions on their websites (I think I printed one from Millet scopes that was pretty cool).

Whatever you get, you can get used to it quickly if you use it and print out the appropriate tables.

One issue is that most variable scopes are only 'calibrated' for their dots/bars at one specific power setting - usually that setting isn't precisely selectable (it will be the usual 'zoom' dial), so you'll want to verify the actual calibration using a clearly visible target.

Then you get to the 'fun' part of using actual ammunition and an actual range, to see what 'dot' you need to use at a particular range for your particular load.

Sometimes when I have to mess with all that, I can see why folks just get a .22-250, 7mm Rem Mag, or .338 Lapua, and "don't bother" with adjusting for 'range' unless it's out beyond 400 yards or so...
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markinalpine
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Re: OT: "mrads" instead of "moa"

Post by markinalpine »

This site: http://www.mil-dot.com/articles/the-mildot-reticle
probably has more than you want to know about MILDOTS, milrads, and even includes an explanation of MOA, Minute Of Angle. :shock:

Mark :lol:
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Goat
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Re: OT: "mrads" instead of "moa"

Post by Goat »

I finally found it on the Vortex website.
"The Mrad reticle is based on the milliradian,mrad for short. Mrad unit of arc measurements are based on the radian. A radian is the angle substended at the center of a circle by an arc that is equal in length to the radius of the circle. There are 6.283 radians in a circle and 1000 milliradians in a circle. These angular measurements are used for ranging and to correct for bullet trajectory drop in riflescopes. An mrad will substend 3.6 inches at 100 yards."
At least this is what Vortex has to say.
Goat
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vancelw
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Re: OT: "mrads" instead of "moa"

Post by vancelw »

BobM wrote:Milliradian. If I remember correctly one "mil" is 3.6" @ 100 yards, one meter at 1000 meters.
It took me a second to switch my brain from degrees/minutes to radians, but I do believe you are correct. I can see the advantage of using radians versus the way we normally see it done. Much easier to calculate.
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vancelw
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Re: OT: "mrads" instead of "moa"

Post by vancelw »

Goat wrote:I finally found it on the Vortex website.
". . .There are 6.283 radians in a circle "
Goat

There are exactly 2(pi) radians in a circle, so 6.283 is an approximation (as is 6.28318530718 ), but we don't need to know that. All we need is the distance to target, which equals one radian. So a mrad is 1/1000th of the distance from the muzzle to the target.

I think I'll baffle my friends with new terminology from now on. :D
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Re: OT: "mrads" instead of "moa"

Post by AJMD429 »

vancelw wrote:I think I'll baffle my friends with new terminology from now on. :D
Like they say, "if you can't dazzle them with brilliance, then baffle them with bull[stuff]..." :lol:

Of course maybe "mrads" refers to the millirads of radiation you'll get if it is one of those fancy glow-in-the-dark reticles... :o
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Cast Bullet Hunter
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Re: OT: "mrads" instead of "moa"

Post by Cast Bullet Hunter »

A mil is 1/6400 of a circle. At 100 yds a mil subtends approximately 3.534". For practical purposes 3.6" is close enough.
RustyJr
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Re: OT: "mrads" instead of "moa"

Post by RustyJr »

If you are wanting something that you can use for up close as well as long range, you might want to look into an aimpoint and a magnifyer. The aimpoints come wth dots that are either good for either 2 moa or 4 moa. The magnifyers mount behind the the red dot rectical. If you need to clear a room you swing the magnifyer out of the way and use the red dot without any magnification. If you need to engage a target at a longer range you just swing the magnifyer in place behind the red dot and its just like using a low powered scope. Ive never used this setup before but some do like it. As with any longarm that uses a scope or especially electronic sights I'd suggest having a set of backup iron sights and know how to use them in the event that your other sights fail. A weapon mounted light would be another valuable tool that you might want to think about.

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Re: OT: "mrads" instead of "moa"

Post by creosote »

My favorite old uncle gave me a m1917 machine gun quadrant he bought for .50 cents many years ago.
It is set up for Rads but he needed degrees and he found a simple{to Him} method.
He etched 177 on it and used it to set up his machines for degrees by using that number
and a simple formula that I know longer remember,

He was a machinist at Rohr Aircraft in California.
creosote
BobM
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Re: OT: "mrads" instead of "moa"

Post by BobM »

RustyJr wrote:If you are wanting something that you can use for up close as well as long range, you might want to look into an aimpoint and a magnifyer. The aimpoints come wth dots that are either good for either 2 moa or 4 moa. The magnifyers mount behind the the red dot rectical. If you need to clear a room you swing the magnifyer out of the way and use the red dot without any magnification. If you need to engage a target at a longer range you just swing the magnifyer in place behind the red dot and its just like using a low powered scope. Ive never used this setup before but some do like it. As with any longarm that uses a scope or especially electronic sights I'd suggest having a set of backup iron sights and know how to use them in the event that your other sights fail. A weapon mounted light would be another valuable tool that you might want to think about.

RustyJr
This makes a whole lot of sense to me. I've got a couple of Aimpoints and I do plan on getting the magnifier as well. The AP magnifier is only 3x but should work for what I want.
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