1 MOA Question

[Xerothermic]

I measure with Cherrios

View attachment 1519732

Hah! I only glanced at the pic and thought "minute of donut."

 

[old_heli_logger]

You'll never get those kind of groups with a donut

 

[ronsatspokane]

Minute of Angle (MOA) is an angular measurement (1/60th of a degree, 1.047 inches at 100 yards). MOA as such is not a metric for measuring scoring. You could have an MOA shooting firearm and not have a group within any of the scoring rings on the target. Or maybe the group is hitting out between the 7&8 rings. At 100 yards the group may be within the 1.047” of MOA but the has nothing to do with scoring.

F Class targets have a 1 MOA 10 ring. X ring is 1/2 MOA. ~3 inches at 300 yards. ~10 inches at 1000 yards. Unlike many disciplines you need to have all your shots within that MOA 10 ring to clean a target (not drop any points that is).

 

[Brians356]

That's a donut, not a Cherio.
Nice try.

Huh. What load behind those billiard balls?
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[divingin]

On competition targets it's touching the line.

To add to the confusion (and make it harder to correctly score the target), the definition in NRA and International pistol (I don't know what benchrest matches use) is that a bullet hole that is "tangent to" the edge of a scoring ring receives the higher score. While the practical utilization of the verbiage is the same, it implies that the hole need not be visibly touching or breaking the line.

On any five shot group, I've found that if I disregard the worst two "outliers" and measure only the three tightest shots, that I feel much better about the groups I'm getting and talking about it with the guys I meet at the sporting goods store.

A friend of mine shot a 4 and 1 group; four shots in about a quarter inch with one shot thrown out by a considerable distance. He posted it on his Facebook page that night to impress his non-shooting friends; his photo included an index finger pointing to the group, which conveniently covered the errant 5th shot.

 

[Brians356]

To add to the confusion (and make it harder to correctly score the target), the definition in NRA and International pistol (I don't know what benchrest matches use) is that a bullet hole that is "tangent to" the edge of a scoring ring receives the higher score. While the practical utilization of the verbiage is the same, it implies that the hole need not be visibly touching or breaking the line.

No, "tangent" requires touching in mathematical terms. It's still subjective to determine if it's touching, what with ragged edges, one reason why wadcutters are popular in pistol score comps.
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[dellet]

If I understand the question, the answer is yes, the blue dots could be an MOA group. The deception is that the circle would have a different center.

Since none of the blue dots are on the true diameter of the circle, the distance between the outside edge must be less than 1.047”. It would actually depend on the caliber of the bullet. How far the center is off the line.

The green dots, are the most questionable, if the holes are on the true diameter, where is the point of the bullet. For shooting group size, that’s where the argument would be.

Red dots should be sub MOA without question.

The difference between shooting groups and shooting, score.

 

[fkimble@charter.net]

What does scoring a target have to do with measuring a group? Well his pic does look like a target!

And subtracting bullet diameter from outside to outside measurement will give a slightly better number than subtracting actual hole size. None of my bullets make a full diameter hole!

Frank

 

[divingin]

No, "tangent" requires touching in mathematical terms. It's still subjective to determine if it's touching, what with ragged edges, one reason why wadcutters are popular in pistol score comps.
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The second sentence is telling. In practice, you're looking at a diminishing distance between shot boundary and scoring ring, until you can't positively ascertain separation. At that you you are (practically) touching, even though you (physically) may or may not be. My point was that you need not be "breaking" or "touching" the line in a visual sense.

To get back to OP's question, though, I measure the largest outside edge to outside edge of the group, and subtract a bullet diameter. If you zero a set of calipers on a bullet, you can directly measure group size, which is usually measured center-to-center of the 2 furthest-apart bullet holes.