# MOA question

Discussion in 'The Basics, Starting Out' started by earl1704, Nov 26, 2008.

1. ### earl1704Active Member

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If an MOA is (roughly) 1 inch at 100 yds and 2 inches at 200 yds ect. is saying "I shot 1 MOA at 100 yds the same as saying I shot 1 MOA at 1000 yds or 10".

Put another way can I pat myself on the back the same at 100 yds as I woud at 400 yds or 800 yds if I shot a 1 MOA at any distance?

Or is hitting 1 MOA at 1000 yds 10 times or a hunded times harder than hitting 1 MOA at say 300 or 600 yds?

Is there a guide to what is considered a good shot at each distance?

I have read several times a statement such as "I shot a sub MOA at long range". Many times they do not give the distance. Without the distance would the statement mean anything?

Second question, when measuring an MOA I have read (though not from what I consider a reliable source) that you measure to the center of the two bullets furthest away from each other. Is this correct?

2. ### Willys46Well-Known Member

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Shooting MOA gets harder as the distance increase. For most people MOA is a good standard to measure ones self by. As you one gets better you can always set your sites lower. I think you are better than average if you can shoot .75 MOA, Not the best shot but better than average.

Just for argument sake, F-class is shot fopr score using .5 MOA targets. To win you better shoot a clean target with 10+ X's. (10 ring is 1 MOA, X ring .5 MOA).

And yes most measure groups center to center or outside to outside and then subtract one bullet diamater.

Willys

3. ### James JonesWell-Known Member

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Generaly the MOA thing is not a set standard for gauging your groups ,if a guy has a 1 moa gun at 100yds then the chances of him shooting a 10" group at 1000yds is slim , same goes for shooting a 1 moa group at 100 then a 4moa group at 300 , your bullet is in the air alot longer and that allows wind and such to act on it.
What'll screw you up is having a gun shoot a 1 moa group at 100yds then shoot the same size group at 300yds , consistantly , this happens somtimes with some of the realy long VLD style bullets , its known as the bullet "going to sleep" , or settling down. This is why I perfer to do my load development out to at least 200yds , preferably 300yds
So in short no , if you shoot a 1" goup at 100yds then shoot an 8" group at 800 then you deserve a pat on the pack.

To measure your group use a dial caliper and measure outside to outside of the widest edges of the bullet holes and subtract one bullet diameter and that will give you a group size , for instance if you put 4 , 308 rounds through one ragged hole measuring .400" wide at it wides point then you have a group that .092" (Thats realy tight !!) but you shoot your 5th shot cause your an honest guy and don't want to just say the 5 bullet shot clean through the hole and that 5th round lands 1.5" from the rest (center to center) then you have a group size of 1.392"

4. ### Natty BumpoWell-Known Member

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Measuring center-to-center of the two furthest bullet holes measures what's commonly referred to as extreme spread. It's one measure of shot dispersion, but not the only one. I and most other shooters use it because it's very easy to calculate. It has some limitations:

If you shoot 3 shot groups and measure extreme spread, you're evaluating that group based on 2 shots (the 2 holes you measure the distance between). If you decide to shoot a 10 a shot group and measure extreme spread, you're still basing load evaluation on 2 shots (but less likely to get a very small group based on random chance as you might w/ just 3 shots).

The fewer shots you take, the more 'useful' measures like extreme spread, that only use 2 data points, are. As the number of shots increase, there are other measures that are better, but not nearly so simple to calculate. You could make the same case for evaluating chronograph data: your velocity range only uses 2 data points (highest and lowest), while standard deviation includes all data points in its calculation.gun)

Wish I knew of a software program that would allow me to point and click my bullet holes on to the target and let the computer calculate mean radius or some other measure of shot dispersion, but until then, I'll keep measuring extreme spread.

5. ### kcebcjWell-Known Member

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Hey Natty Bumpo

Not to hijack this thread but I think RSI Shooting Lab software has what you might be looking for. I fooled with the trial version a couple years ago and it seems it had a target analyzer built in. Never used it so do not know what results it might produce. The link is below.

Ballistics Software, Chronographs & Pressure Instruments For Shooters

6. ### BuffalobobWriters Guild

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They asked Matt Kenseth why he wouldn't wreck Jimmie Johnson in the last race so Carl Edwards would win the championship. Kenseth's reply was "Common sense".

That is pretty much the answer to your question. A good shot at each distance is that it is within the kill zone of the animal you are hunting. I was very pleased when my daughter finally managed to keep 50 out of 50 shots in the black of an F-class target. That meant she had less than 2% error under controlled conditions on a target roughly the size of an elk kill zone at ranges of 800 yards to 1000 yards with a slow 308 Win. Moving up to a high speed super magnum with ULDs provided her with additional insurance. She made a really beautiful shot on a deer at 700 yards. She was confident and sure of her abilities because she had worked hard to achieve those skills.

So that is the way I see it. You should be capable of consistently placing bullet after bullet into an area that is the size of the kill zone of the animal you hunt and limit the range to the distance that you can achieve those results. In my experience it usually is not so much an issue of distance as it is of wind. A lazer rangefinder will reduce distance errors but wind is really difficult and can cut your effective range down to really trivial distances. When the wind gets over 10 mph I don't like to shoot much over 500 or 600 yards and 600 is really pushing it.

7. ### EagletWell-Known Member

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This is the one you're looking for... you may also download it for free!

OnTarget Software

8. ### Natty BumpoWell-Known Member

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Eaglet and Kcebcj:
Thanks for the replies. Both products appear to fit the bill of what I've been looking for. I've done Google searches trying to find similar software but haven't had any luck.

Earl1704:
You've gotten some good advice here. I'm a long range newbie and only infrequently make the drive to where I can shoot over 100 yards. All I can tell you is that in my experience, a rifle/load that groups 1/2 to 3/4 MOA at 100 yards doesn't necessarily consistently group under 1 MOA at 400 yards. Maybe I need to find loads that have a tighter velocity range (I only got a chronograph this summer), or maybe the problem is me. Keep pluggin' away; I know I will.

By the way; I'm impressed by anyone who can put a few shots inside a few inches at 500 yards. I'm not as impressed with 3 shots inside an inch at 100 yards. Even a mediocre rifle/shooter can get 3 in an inch now and then at 100. The goal is to consistently hit your target; and, with practice, to increase your effective range.

9. ### cva54Well-Known Member

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OK I got 1 here. I got this old rem pre 700 .06 been working on it the only thing left is pillers and bedding a wood stock. At a 100Y 3 1/2" circle with a 1/2 dot in it. Could barley see it but I kept aiming at the same spot. scope turned up to 5 or 6 a 3x9x40. Out of 10 shots had 4 flyers and the other 6 the bigest spreed is 1" center to center. If I mesure from the center HOLE it is no bigger than a 1/2. So what is the MOA? (can some 1 please answer this) If I could put a pic out here I would

10. ### MontanaRiflemanWell-Known Member

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cva, MOA = Minute of Angle which is an arc measuremnet. It is eqivelent to 1/60th of a degree and there being 360 degrees in a cricle. At 100 yds, 1 MOA = approx 1.047". If you want to throw out your fliers, your 6 shot group of 1/2" @ 100 yds = 1/2 MOA

Hope this helps,

-MR

11. ### cva54Well-Known Member

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thank you that is the way I seen it just had to ask

12. ### sscoyoteWell-Known Member

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That's kinda the way i see it too.

A couple years ago i posted somewhere that i was shooting right around MOA with some rig out to ~800 yds. (in good conditions). Some guy slammed me 'cause he thought i said that i could shoot 1" at 800 yds. He wasn't thinking about the "A" part of MOA, which = angular measurement, of course. MOA is just a concise system of explaining what's going on really. Instead of saying i shot around 2" @ 200 yds., 3" @ 300 yds., etc.--by the time i got to 800 yds. the guy i was telling it to would be asleep. The "MOA" term is fast--it's only 3 letters.

BTW, don't forget SMOA too. That's kinda' convenient to know also. SMOA is the bastardization of MOA (instead of 1.0472" per hundred yds. it's the more common inch per hundred yds.--also known as IPHY. so 1 IPHY exactly equals 1 SMOA).

13. ### cva54Well-Known Member

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ok then some one know math a lot better than me LOL