I'm not missing anything. I think some of us could do well by learning the correct method of measuring group size.
No offense intended towards anybody. If benchrest shooters didn't subtract bullet diameter they would all shoot a .17 as it is .191" smaller than a .30 caliber bullet, and .383" smaller than a .50. If you don't think that .191" or .383" matters in a br competition your crazy.
Here is some additional information.
http://en.wikipedia.org/wiki/Minute_of_arc"[edit] Firearms
This unit is commonly found in the firearms industry and literature,
particularly that concerning the accuracy of rifles. The industry
tends to refer to it as minute of angle rather than minute of arc. It
is popular because 1 MOA subtends approximately one inch at 100 yards,
a traditional distance on target ranges. A shooter can easily readjust
his rifle scope by measuring the distance in inches the bullet hole is
from the desired impact point, and adjusting the scope that many MOA
in the same direction. Most target scopes designed for long distances
are adjustable in quarter (¼) or eighth (⅛) MOA "clicks". One eighth
MOA is equal to approximately an eighth of an inch at 100 yards or one
inch at 800 yards.
Calculating the physical equivalent group size equal to one minute of
arc can be done using the equation: equivalent group size = tan(MOA ∕
60)*distance. In the example previously given and substituting 3600
inches for 100 yards, tan(1 MOA ∕ 60)∙ 3600 inches = 1.0471975511966
inches.
In metric units 1 MOA at 100 meters = 2.90888208665722 centimeters.
Sometimes, a firearm's accuracy will be measured in MOA. This simply
means that under ideal conditions, the gun is capable of repeatedly
producing a group of shots whose center points (center-to-center) fit
into a circle, the diameter of which can be subtended by that amount
of arc. (E.g.: a "1 MOA rifle" should be capable, under ideal
conditions, of shooting a 1-inch group at 100 yards, a "2 MOA rifle" a
2-inch group at 100 yards, etc.) Some manufacturers such as Weatherby
and Cooper offer actual guarantees of real-world MOA performance.
Rifle manufacturers and gun magazines often refer to this capability
as "Sub-MOA", meaning it shoots under 1 MOA. This is typically a
single group of 3 to 5 shots at 100 yards, or the average of several
groups. If larger samples are taken, i.e. more shots per group, then
group size typically increases. [2]"
http://www.tacticaloperations.com/" The workmanship and attention to detail on the prototype were
superb, but what really intrigued me were the sub-1/4 minute of angle
(MOA) accuracy claims that he made for the rifle. I figured that this
guy had to be either full of BS or had come up with a better way of
doing things. As we talked further, I suspected the latter had to be
the case. Still, I remained a skeptic. "