ive been looking into optic's, and i keep seeing MOA on everything...i understand it stand's for "minute of angle"...but what is MOA? is it possible to pick an optic that is the wrong MOA for my rifle? i have no clue what MOA is.. for example: EOTech 512= reticle is 65 MOA ring w/ 1 MOA dot. Aimpoint Comp ML2= 4MOA

It shows how accurate it is. Basically 1 MOA means a 1" circle at 100 yards. I think it's a little bit off of that, but it's close enough.

Minute of angle is pretty complicated, we all use the approximation to make it easy. The approximation is: At 100 yards it is 1"... so if you are 3 MOA too low at 100 yards, it means you are 3" too low @ 100 yards. Normally 4 clicks on a scope = 1 MOA. So if you are 3" too low at 100 yards then it means you need to go 12 clicks up, thats if your scope is 1/4 MOA per click. Some scopes are 1/8 MOA per click, some 1/2 MOA. At 200 yards 1 MOA = 2" At 300 yards 1 MOA = 3" etc etc MOA can also be used to measure groupings. If someone says I am 1/2 MOA groups, it means he is 1/2" at 100 yards, 1" at 200 yards, and 2" at 400 yards, etc.

Also, that means at 200 yards it's 2", 300 is 3", and so on. 2 MOA would double those figures. 1/2 MOA would halve them.

hmm...that clears it up a little better. so say i put an eotech 512 on my rifle, and at 100 yard's im 5 inches to low....would i go up 5 click's? because it is 1 MOA?

Generally speaking 1 click is 1/4". So 4 clicks/ MOA @ 100 yards. YMMV with whatever optics you're using. I've only used some basic hunting scopes. Check the manual to make sure it is the same for you.

I dunno...you have the manual, not me. Worst case you can either try it and find out for yourself, and contact the manufacturer, they would be able to tell you for sure.

i dont have a manual, or an optic yet...im trying to understand MOA, because i keep coming across it while planning the optic for my build.

The confusing thing about minutes are we think it's a measurement of time. Funny thing is, it's also a measurement of degrees. For every 1 degree, there is 60 minutes For every minute it's 1/60th of a degree So MOA or Minute of Angle is just a smaller than 1 degree measurement. Here's a link to really confuse you Mil-dots and Minutes-of-angle - From a Technical Perspective Hope this helps.

+1 to everything you said. That's why most of us like to keep it simple. 1" @ 100 yards, 2" @ 200 yards.. etc

You are confusing the reticle with the adjustments. The adjustments on the Eotech 512 is 1/2 MOA. So if you are 5" too low you need to go 10 clicks up. Now the reticle is another thing. The outside ring is 65 MOA. The dot is 1 MOA. So what this mean is: @ 100 yards that dot = 1" and the ring = 65" @ 200 yards that dot = 2" and the ring = 130" etc etc

One other thing, When you are talking about Eotechs and red dot sights like the Aimpoint. The manufactures list the size of the dot in MOA. So if the Eotech says 1 MOA dot 65 MOA circle it means that the reticle dot appears to be 1" in diameter at 100 yards and the circle around the dot appears as 65" in diameter. The Aimpoint dot appears to be 4" in diameter at 100 yards. The smaller dot will be a bit more precise, but the larger dot will be easier to see. Eotech's reticle with the 1 MOA dot and 65 MOA circle is a compromise of a smaller dot for accuracy and a big circle for speed up close. ie if they are inside the room with you just get their body in the circle and start pulling the trigger.