Noob question. What is MOA?


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SciFiJim
March 4, 2009, 08:04 PM
I have seen in various forums that someone's rifle shoots 0.xxx MOA. Is that the size of the group of shots? How many shots do you shoot for the test and at what range? Some of the groups seem insanely small. Like under half an inch. I could understand if the target is close and the rifle is in a vise. Or should I take these measurements with a large grain of salt and some "Kentucky windage"?

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Pulse
March 4, 2009, 08:17 PM
I have seen in various forums that someone's rifle shoots 0.xxx MOA. Is that the size of the group of shots?

http://en.wikipedia.org/wiki/Minute_of_angle#Firearms

NOTE: there is also the shootersMOA, wich is 1inch@100yards, very small difference to a actual MOA, but substntial enough to screw up very long shots.

How many shots do you shoot for the test and at what range?

for a actualy meaning full report on accuracy you should take the average of multiple 5 or even 10 shot groups at what ever range you want to use the rifle at.
most are happy with a single 3 shot group at 100yards

Or should I take these measurements with a large grain of salt and some "Kentucky windage"?

you can normaly see from the way it is Writen on how mutch salt you have to take.
if you see someone claiming that his 500dollar semi-auto Rifle with 30-40 year old Surplus ammo or random factory ammo can shoot 0.5inch at 100 yards.. then you shoud order several buckets of Salt.
if you see someone posting a detailed recipe for his handloads, with a proper Rifle and good Glass, claiming that his Rifle can shoot a average of ~1MoA at 100yards, then that is mutch mutch more believable.

bhk
March 4, 2009, 08:18 PM
It is 1/60 of a minute of angle, which translates into about one inch at 100 yards (two inches at 200 yards, etc.).

A MOA group is a group of shots were the two furthest apart shots (generally measured from the center of the bullets holes) are one inch apart.

Art Eatman
March 4, 2009, 08:20 PM
MOA = Minute of angle. It's right at 1" per hundred yards of distance. So, 1 MOA is 1" at 100 yards, 2" at 200 yards and so on.

The exact measurement begins with a circle having 360 degrees and each degree having 60 minutes or 21,600 minutes, total for the circle. Do the trigonometry for a circle of 100 yards--which is 3,600 inches. I ain't gonna. :)

Bench rest shooting for competition is for five-shot groups. You are not competitive unless your five shots measure less than 0.1 inches in dispersion, center-to-center.

I use sand bags on my bench rest. I tweak and fiddle with bedding of the forarm and with tailor-made handloads so that my hunting rifles provide 1/2-MOA groups for three shots. Some have been pretty good at holding that for five shots. I have an "attitude" that only the first shot is what's really important when I hunt. :)

In today's world, with the quality of today's machine tools, there are few rifles that WON'T shoot inside of one MOA.

Experience plays its part, of course. I've been loading for and shooting centerfire rifles since 1950. Back some ten years ago I set up a 500-yard range, here at the house. Now, I commonly zero my rifles for 200 yards. With my .30-'06 zeroed in that manner, I have to allow for right at four feet of drop at 500 yards.

Okay, says me, "Play time." I had to guesstimate four feet of holdover and allow for a breeze--so I held about a foot of daylight to the upwind side. My first shot was about six inches low at 5:30; the next was one inch low at 6:00. I figured that wasn't bad for an Olde Phart with tri-focals.

Lotsa guys here can do better...

Art

Jim K
March 4, 2009, 08:35 PM
It is convenient, but pure coincidence, that 1 MOA is almost equal to 1" at 100 yards. Not quite, but close enough.

Using the term MOA saves saying what size group at what range, but can be deceiving, since many factors combine to increase shot dispersion. 1" groups at 100 yards are fairly common, but it is a rare rifle that do that and then stay in 2" at 200 and 4" in 400. And groups under 10" have been fired at 1000 yards, but not from your average hunting rifle.

Jim

Zak Smith
March 4, 2009, 08:37 PM
We just had this discussion not two weeks ago.

http://www.thehighroad.org/showthread.php?t=431275&highlight=moa

SciFiJim
March 4, 2009, 09:41 PM
Zak,
I missed that one. Thanks for pointing to it. It has really good info. What I've learned it that either I am a terrible shot or my rifle is garbage. I have a .357 Marlin 1894 and am lucky to get a pattern a foot across at 100 yards with 5 shots. I am also learning to reload so perhaps I might be able to tailor a load that shoots more accurately. After all it cant be moi.:confused:

proud2deviate
March 4, 2009, 09:44 PM
Bloody big birds. Extinct.


See also: Mall Of America.

publiuss
March 4, 2009, 11:06 PM
sci-fi-jim, you're not a terrible shot, and your gun isn't junk. it's just not intended to be a MOA gun. It's a pistol round carbine meant for fairly close range work.

SciFiJim
March 5, 2009, 01:44 AM
So if I work on developing a good round for it what should I expect to see as repeatable results at 100 yards? I am thinking about Cast Performance (http://www.castperformance.com/Categories.bok?category=Cast+Performance%3A357+Cal.) 180gr. WFNGC bullets for it. I would like it for targets as well as the wild pigs that we have running around here.

REAPER4206969
March 5, 2009, 02:30 AM
Zak,
I missed that one. Thanks for pointing to it. It has really good info. What I've learned it that either I am a terrible shot or my rifle is garbage. I have a .357 Marlin 1894 and am lucky to get a pattern a foot across at 100 yards with 5 shots. I am also learning to reload so perhaps I might be able to tailor a load that shoots more accurately. After all it cant be moi.

What position are you shooting these groups from?
You have to remember that all of these ~MOA groups are fired from supported bench/supported prone positions. Your Marlin should be at least a 2 MOA carbine.

SciFiJim
March 5, 2009, 10:15 AM
I am shooting from a bench, rifle supported by sand bags. I AM using iron sites until the scope I ordered comes in. It could be my eyes. Durn those young people's eyes.
Thanks Reaper,
Now that I know the limitations of my carbine, I can work on eliminating the human error to get to a 2 MOA grouping. When I can do that I will do a happy dance on the firing line (well... maybe behind the safety line):D

n00b
March 5, 2009, 10:36 AM
SciFiJim,

Have you had any training?

The "Nut" behind the sights is more important than the rifle. If you are not a 1MOA shooter the rifle in your hands will never be a 1MOA rifle.

And most "good" shooters are NOT even 4MOA shooters... Much less 1MOA.

Get to an Appleseed... They will give you the "Basics" just as the Marines would give you the basics of Marksmanship.

http://www.appleseedinfo.org/

Remember the Marines are like no other service in that every Marine must make "Marksman". Other services consider a "Marksman" score an improvement over the average "Joe".

Appleseeds are some the best training you can get and CHEAP too! 2 days will cost you $70 and you will most likely not walk away a Rifleman (Expert) but you will take home the knowledge and tools need to get there!

Bwana John
March 5, 2009, 10:39 AM
Real men use radians. :evil:

SciFiJim
March 5, 2009, 11:00 AM
Back in the day... about 20 years ago, while I was in the Naval reserve, I spent an enjoyable weekend at the China Lake naval base shooting range burning up government provided ammunition with a government owned M16. I missed qualifying as expert by ONE point. I still have my sharpshooter's ribbon :) Since then I haven't shot at all. This last year I purchased my first rifle (.357 Marlin 1894) and my first handgun (.45 acp Kimber UC II) to get back into shooting. The relearning curve is steeper than I thought. I can see that I need to get some training from someone that can spot my errors and help me to correct them. I will look into the appleseed program.

SciFiJim
March 5, 2009, 03:42 PM
I just found an interesting article by Chuck Hawks on practical accuracy (http://www.chuckhawks.com/practical_accuracy.htm) that is very interesting. It describes what I can expect from my rifle and the practical applications for it.

REAPER4206969
March 5, 2009, 07:30 PM
Just so you are aware, 2MOA is 2 (Two.) inches at 100 yards and the group is measured from the CENTER to the CENTER of the two farthest apart holes. If you are having trouble seeing at 100yrds shoot at 50yrds.
At 50yrds, a 2MOA group is 1 (One.) inch.

:)

REAPER4206969
March 5, 2009, 07:40 PM
Part 1:http://www.youtube.com/watch?v=R_PFd9YpRzk

Part 2:http://www.youtube.com/watch?v=xFDNNV83M6Q

Part 3:http://www.youtube.com/watch?v=XTDxVcusrVM

Here is a WW2 basic Rifle Marksmanship training video.
It will help you re-learn the basics.:D

REAPER4206969
March 5, 2009, 07:56 PM
http://media.midwayusa.com/midwayusa/StaticPages/highres/885983.jpg
http://www.midwayusa.com/viewProduct/?productNumber=885983

I have no experience with the .357 S&W MAGNUM loadings, (I have a Marlin 336A in .30WCF.) but I have heard good things about them from people with your exact carbine.

REAPER4206969
March 5, 2009, 08:16 PM
Clint Smith
Elements Of Rifle Skill

http://www.youtube.com/watch?v=rKAuP9_Ha8Y

SciFiJim
March 5, 2009, 08:50 PM
Thanks Reaper

REAPER4206969
March 5, 2009, 08:59 PM
You are welcome! How were the videos?

SciFiJim
March 5, 2009, 11:53 PM
Very informative. One of the things that I have done wrong is resting the rifle on the sand bags instead of my hand. Another is that I have held the rifle looser instead of tight to my body. Another error is holding the rifle too low when shooting off hand and having to crane my neck to see the sight picture. I will have to try the right way on my next trip to the range and see what it gets me.

REAPER4206969
March 6, 2009, 11:59 PM
I am glad I could help.
;)

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