When one is talking about shooting and groups. What does the term MOA mean. For instance, I read this, "Rifle is fully capable of sub moa groups as it sits"

Look in the Sticky's in this heading (General Rifle Discussion). There is a very good one there on MOA.

moa stands for minute of angle. its 1.047" at 100yards. we tend to round it to 1" everytime the distance doubles so does that moa. so at 200 yards its 2.094" when you get out to 1000 yards its 10.47" if your scope has moa adjustments of 1/4 moa at 100 yards it will move the impact .26175 at 200 yards it will move .5235 inches and at 1000 yards each click will move the impact 2.6175 inches. when you go the other way from 100 to 50 the ammount of moa is divided in half whenver the distance decreases by half. so at 50 yards 1 moa is .5235 and each click will move impact by .130875 inches and so on.

its a division of a circle with 360 sections. kinda like a slice of pie. if the pie was 100 yards diameter each slice would be 1.047 inches wide at the edge. no matter how big the circle is the outer edge will be a certain distance wide and gets wider and smaller at a known ratio. its how navigators navigate and how artillery is aimed. it also translates into shooting because you can use that measurement to determine how far away an object is and how much adjustment is needed for a bullet to strike an object at a given distance.

Or MOA for dummies like me . 1" spread per 100 yards. .5" spread at 100 is sub moa. 2" spread at 100 yards is 2moa

In most basic terms, it means you can put 3 rounds in a space the size of a @ quarter, at 100 yards. It IS a lot more complicated than that, but it's basically what it boils down to.

at 100 yards its about 1 inch. if your group measures .999 inches or less your shooting sub moa. sub is a prefix to words meaning its whatever the word is less of that. like marine means having to do with water submarine means under the water. subtract means make less of. so submoa would be less than moa

Sub moa is less than 1 inch at 100 yds (more or less) This shot group fired at 100 yds is a bit over a half inch wide. That is sub MOA. Moa would have been a 1 inch group at that distance. Not my target- pic I grabbed to illustrate-

Sub MOA is any shot spread below its corresponding 1" per 100 yard ratio. Again 1" grouping at 100 yards is 1 MOA so if you had a 1/2 in grouping at 100 yards that is .5 or sub moa. That works the same all the way up the ladder. 3" spread at 300 yards is 1 MOA anything below 3" at the range is sub MOA just depnds on how much 1" spread at 300 yards would be I believe .33 MOA

Basically sub, in this instance simply means "less than". So "sub-MOA" would mean you could cover the three holes in a target, at 100 yards, completely, with a nickel, give or take.