meanmike8665
45 Cal.
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How does one measure group size? Center to center, outside to outside, inside to inside or what?
Thanks, Michael
Thanks, Michael
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measuring group size
- Thread starter meanmike8665
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Techniquely a scored group is Center to Center of the two furthest points.
Outside to outside at the farthest point is easiest for me,,
then subtract one ball diameter.
Let's say outside to outside is 1 1/4"s shooting 54 with a .530 ball.
1.250 - .530 = .72,, roughly a 3/4" group.
(thats the same as center to center, but you don't have to guess at where center is)
Outside to outside at the farthest point is easiest for me,,
then subtract one ball diameter.
Let's say outside to outside is 1 1/4"s shooting 54 with a .530 ball.
1.250 - .530 = .72,, roughly a 3/4" group.
(thats the same as center to center, but you don't have to guess at where center is)
meanmike8665
45 Cal.
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Thank you, I now understand measuring groups means. I have been shooting a long time, never group size, but score, if they stay in the 9 ring on a NMLRA round ball target that is good enough. Thanks again.
Michael
Michael
BE Wild Willy
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I was taught to do it as Necchi shows.
the outside of the hole to the inside method is more accurate as the hole in the target is often not exact bullet diameter so the math can be off.But the outside edge method regardless of hole size is accurate.No math needed and much simpler than the other method.Why make it harder than it needs to be?
George
George
hanshi
Cannon
You're right but it takes away the opportunity to lie (just a little bit) and "fudge". :grin:
Rat Trapper
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Take your calipers and measure from the outside of the two shots that are farthest apart. Then subrate the bullet dia. Or just measute from what you think is the center of those two bullet holes.
zimmerstutzen
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If I shoot a group that can be covered with a half dollar, it doesn't mean a half dollar plus a ball diameter.
A group is distance between the farthest edges of the two outermost holes.
If a score is by string measure, that may be different depending on the club.
I once saw a post in which the author claimed to have shot a .47 inch group with a 58 caliber rifle. See how ludicous that sounds? By my method of measurement a group can never be under ball size. His group would have been 1.04 assuming a .570 round ball.
Some clubs score by the innermost edge of the hole, some by the center of the hole.
Hoppy of H&H barrels came up with a special offhand rifle just for those matches that scored by the inner edge. As I recall it was a 72 caliber offhand rifle. He figured it gave almost a fifth of an inch advantage, over a 440 round ball) with each shot.
A group is distance between the farthest edges of the two outermost holes.
If a score is by string measure, that may be different depending on the club.
I once saw a post in which the author claimed to have shot a .47 inch group with a 58 caliber rifle. See how ludicous that sounds? By my method of measurement a group can never be under ball size. His group would have been 1.04 assuming a .570 round ball.
Some clubs score by the innermost edge of the hole, some by the center of the hole.
Hoppy of H&H barrels came up with a special offhand rifle just for those matches that scored by the inner edge. As I recall it was a 72 caliber offhand rifle. He figured it gave almost a fifth of an inch advantage, over a 440 round ball) with each shot.
For a center to center measurement, there's NO outside to inside measurement unless I'm not understanding what your saying. The simplist and most accurate is to measure from the same side of each of the 2 fartherest apart holes, such as the LEFT side of one to the LEFT side of the other. that gives you an exact place to measure from and an exact place to measure to and is exactly the same as measuring from center to center especially when your guessing where the center is.
The important thing especially with a ML is where the 1st shot goes and the distance it is from the point you were aiming at.
Deadeye
The important thing especially with a ML is where the 1st shot goes and the distance it is from the point you were aiming at.
Deadeye
Paulab, that's exactly right, caliber has nothing to do with group size. I just read that Jim Carmichael just won the light Varmint rifle benchrest championship, 5, 5 shot groups, .1" groups. 25 .244 bullets in .1" group, close to 1 hole.
Deadeye
Deadeye
Hmmm. I can't do this, but I've seen a ragged hole shot with a .54 at 25 yards. It would have been a real guess as to where the centers were and there was no "inside" to measure. Had to measure outsides and subtract the ball diameter. Maybe that formula is the only one that would work all the time, especially with great shooters who can cloverleaf a group. Fuzzy
Thank you.
