scope MOA = x inches?
- Thread starter taliv
- Start date
- Status
SSN Vet
Member
at 100 yds one moa = 1.05"
usually rounded to 1"
usually rounded to 1"
Vern Humphrey
Member
What is the question?
A minute of angle is just about 1" at 100 yards -- no matter what scope you are using.
Now if you're asking what value is a "click" or single adjustment movement, that's usually 1/4 MOA -- but refer to your owner's manual to be sure.
If your scope is not click adjustable, then the marks are usually from 1 to 1/4 MOA. Again, refer to your owner's manual.
my question is simply, what is it precisely with various scopes?
i was looking at some ballistic software and it lets you select inches/MOA @100yds, and has in the notes, that leupold scopes are actually of 1.05" and nightforce scopes are 1.09". I happen to have leupold and nightforce scopes (with 1/10th MOA and 1/8th MOA adjustments respectively) but I also have a swarovski, and that wasn't listed. So what i was really hoping for was the swarovski measurement, but I thought a list of them might make for a good addition to zak's scope guide.
Vern Humphrey
Member
It's always the same, regardless of the scope.
i
A minute of angle is always a minute of angle. That translates to a chord of 1.05" at 100 yards and an arc 1.09".. Precisely what the value of a click is may differ -- but that doesn't change the value of a minute of angle. To know what the values of the clicks are for your scope, check the owner's manual.
Mute
Member
What he means, I believe, is that some scope makers use IPHY (1 Inch Per Hundred Yard) MOA while others use TMOA (1.047" @ 100 yards) for their MOA reticles and click values.
I've never seen a compilation of this information before, but I do know that Nighforce uses TMOA and Leupold uses both depending on who you ask, on which day.
I've never seen a compilation of this information before, but I do know that Nighforce uses TMOA and Leupold uses both depending on who you ask, on which day.
Art Eatman
Moderator In Memoriam
360 degrees in a circle. 60 minutes in a degree. So, 6 x 3,600 = 21,600 minutes in a circle.
For a 100-yard radius, multiply by 2 x Pi (3.141521, IIRC) and then by 36 to get the inches around the circle.
Then divide inches by minutes.
Or just take 1/3 Pi.
Anyhow, one MOA = 1.0471 inches at one hundred yards. It's "close enough for government work" to call it one inch per hundred yards.
For a 100-yard radius, multiply by 2 x Pi (3.141521, IIRC) and then by 36 to get the inches around the circle.
Then divide inches by minutes.
Or just take 1/3 Pi.
Anyhow, one MOA = 1.0471 inches at one hundred yards. It's "close enough for government work" to call it one inch per hundred yards.
Mute
Member
At a hundred yard 1" vs. 1 MOA is close enough, however, at extended distances, if you don't know which one your scope uses, when you run a ballistic calc to get you on target, there could be enough disparity to make you miss your target all together.
Of course it's a moot point once you know which one your equipment uses. Besides you should get all the dope on your rifle by shooting it at varying distances anyway.
Of course it's a moot point once you know which one your equipment uses. Besides you should get all the dope on your rifle by shooting it at varying distances anyway.
yeah, yeah, there's no secret to the math behind MOA.
It's also no secret that in any field, ACTUAL measurements are almost ALWAYS different from the marketing. For instance, a "2x4" piece of lumber isn't. Is it close enough? depends on what you're doing. "223 Rem", "480 Ruger" etc aren't either.
and as most of you noted, "1 MOA" is not "1 inch at 100 yrds". Yeah, it's close enough for just about anything, but I still want to know precisely what some of the scopes use for no other reason beyond my personal amusement.
It's also no secret that in any field, ACTUAL measurements are almost ALWAYS different from the marketing. For instance, a "2x4" piece of lumber isn't. Is it close enough? depends on what you're doing. "223 Rem", "480 Ruger" etc aren't either.
and as most of you noted, "1 MOA" is not "1 inch at 100 yrds". Yeah, it's close enough for just about anything, but I still want to know precisely what some of the scopes use for no other reason beyond my personal amusement.
SNEAKY PETE
Member
Sneaky here: Math 101--21600 min in a circle and 3600 inches in 100 yds therefor circumfrence=2 x pi(3.141592654) x radius =22,619.46711 inches then divide by 21600min =1.047197551 " @ 100 yds. (sorry my calculator won't give me pi with any further decimals) 1" @ 100 is cool, but @ 1000 it more likely 10.5 " Not bad for an old M/sgt ??? THANX--SNEAKY
Your thinking too much, like I did when I got into long range shooting.
Everything looks good on paper: one moa = 1 inch at 100 yards or 1.05 at 100 yards. In real life, it's pretty much meaningless when you consider powder, brass weight, neck thickness, neck tightness, primer variations, etc, etc, etc, etc.
Your goal is consistency. If you reload and can shoot 1/2 inch moa groups at 100, fine, for hunting, 2 moa is fine.
But to answer your question. MOA or Moment of Arc is one degree of arc angle. This increases exponentally as distance increases. Well it's actually more of a linear function then exponential. Easy to multiply x 2 for each 100 yards and you got your moa for that distance.
Sooo, two moa at 100 yards is two inches. Two moa at 200 yards is four inches (2 x (200/100)). Think cone here. Two moa at 1000 yards is 20 inches (2 x (1000/100)). That's probably the simplest example I can give. Weather it be 20 inches or 20.5 inches should not be a consideration... wind, density altitude, barametic pressure, elevation, and all the other stuff will make this immeteraial.
You just want to be 'good enough' to kill your prey. Don't sweat the small stuff, load consistly, know your limitations, and practice, practice, practice!
Everything looks good on paper: one moa = 1 inch at 100 yards or 1.05 at 100 yards. In real life, it's pretty much meaningless when you consider powder, brass weight, neck thickness, neck tightness, primer variations, etc, etc, etc, etc.
Your goal is consistency. If you reload and can shoot 1/2 inch moa groups at 100, fine, for hunting, 2 moa is fine.
But to answer your question. MOA or Moment of Arc is one degree of arc angle. This increases exponentally as distance increases. Well it's actually more of a linear function then exponential. Easy to multiply x 2 for each 100 yards and you got your moa for that distance.
Sooo, two moa at 100 yards is two inches. Two moa at 200 yards is four inches (2 x (200/100)). Think cone here. Two moa at 1000 yards is 20 inches (2 x (1000/100)). That's probably the simplest example I can give. Weather it be 20 inches or 20.5 inches should not be a consideration... wind, density altitude, barametic pressure, elevation, and all the other stuff will make this immeteraial.
You just want to be 'good enough' to kill your prey. Don't sweat the small stuff, load consistly, know your limitations, and practice, practice, practice!
Zak Smith
Member
Actually, taliv isn't "thinking too much." There is much confusion surrounding which scopes/mfgrs use "true MOA" vs. "shooters MOA" (aka IPHY).
The best answer you are likely to get without testing the scope itself is to call the mfgr and ask a tech. I do recommend "box testing" scopes right after you get them mounted (provided the rifle, load, and you have enough consistency to give the test meaning).
The best answer you are likely to get without testing the scope itself is to call the mfgr and ask a tech. I do recommend "box testing" scopes right after you get them mounted (provided the rifle, load, and you have enough consistency to give the test meaning).
Good call Zak, understood.
What I'm trying to do is get him away from the details.
For example, say you have your zero set for 75 and 200 yards with a 308 round. You know your an inch or so high at 100. Fine. All is good within 150 yards.
Now you see a prong 400 yards out. How many clicks on your scope's elevation do you need to zero for 400?
That's the practice I'm talking about. This is possible with good quality rounds without reloading.
In most cases, MOA is measured at the scope's maximum magnification. This can be easily verified at the range.
What I'm trying to do is get him away from the details.
For example, say you have your zero set for 75 and 200 yards with a 308 round. You know your an inch or so high at 100. Fine. All is good within 150 yards.
Now you see a prong 400 yards out. How many clicks on your scope's elevation do you need to zero for 400?
That's the practice I'm talking about. This is possible with good quality rounds without reloading.
In most cases, MOA is measured at the scope's maximum magnification. This can be easily verified at the range.
Zak Smith
Member
Bitswap,
The "trial and error method" of generating come-ups means starting over whenever you change some of the relevant parameters. If you know the click values (true MOA, shooters MOA, or something wierder), then you can generate the new click values directly without starting over.
Also, counting clicks is slow. The knobs are annotated with numbers for a reason-- dial directly to the dope required.
-z
The "trial and error method" of generating come-ups means starting over whenever you change some of the relevant parameters. If you know the click values (true MOA, shooters MOA, or something wierder), then you can generate the new click values directly without starting over.
Also, counting clicks is slow. The knobs are annotated with numbers for a reason-- dial directly to the dope required.
-z
No Zak, I'm not talking about trial and error.
You use math to determine how much moa you need to reset your zero to 400 yards in my example above, then set your scope to it. It is easier with a mili dot rectile though. I'd never advocate 'trial and error'. Long range shooting is a science with a tad of luck thrown in.
You use math to determine how much moa you need to reset your zero to 400 yards in my example above, then set your scope to it. It is easier with a mili dot rectile though. I'd never advocate 'trial and error'. Long range shooting is a science with a tad of luck thrown in.
Zak Smith
Member
And if your knobs are actually "shooter's MOA" (IPHY) or are otherwise off from true MOA (as in taliv's example), then knowing the MOA come-up and dialing that on the scope will have error built in. That is the point of knowing the actual click values of your scope, and the point of this thread.
SNEAKY PETE
Member
Old Sneaky here: I just got a Brain Fart--Think about this- Are we actually talking about Arc distance or Tangent distance ??? Oh my Old M/sgt brain hurts just contemplating this dilema. I need some serious help--BUT I don't know if it's math or reality. THANX --SNEAKY
deadin
Member
Hey guys, you're arguing about .047". That's less that a half inch at 1000 yds.
Got a rifle that can vary less than a 1/2 " at a 1000? If not, what's the point?
Got a rifle that can vary less than a 1/2 " at a 1000? If not, what's the point?
Vern Humphrey
Member
Hey, at 1,000 yards, that could cause you to miss the whole target (I know because someone posted it here.)
At 2,000 yards, the difference wouldn't quite amount to an inch. I'd really lose sleep over that.
Outlaws
Member
Bwana John
Member
- Joined
- Sep 10, 2004
- Messages
- 2,960
Dude,
Dont sweat the small stuff, the differance is so small that you will not be able to quantify it, because of other factors that affect the projectile more (range estimation, temperture, relitive humity, elevation, corialis effect, manufacting difference in projectiles....)
If we are going to worry about the small stuff, what about scopes that use 6400 mil-radians to a circle instead of 6283!
Dont sweat the small stuff, the differance is so small that you will not be able to quantify it, because of other factors that affect the projectile more (range estimation, temperture, relitive humity, elevation, corialis effect, manufacting difference in projectiles....)
If we are going to worry about the small stuff, what about scopes that use 6400 mil-radians to a circle instead of 6283!
- Status
