The following quote from a post in the rifle forum got me thinking about groups and how they are measured. I always thought that groups were measured from the outside edges of the holes. Is there a standard way to measure groups? How do the judges at the national matches measure them?
How do YOU Measure Your Groups?
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The following quote from a post in the rifle forum got me thinking about groups and how they are measured. I always thought that groups were measured from the outside edges of the holes. Is there a standard way to measure groups? How do the judges at the national matches measure them?
fourdeuce82d
Member
I like to keep 7 yard "aimed" shot's within about a two inch circle- double taps within four... every now and then I'll do a four-five round "hose"...and if everything's within a salad plate sized area...it's good.
Tamara
Senior Member
Center to center is the way they are supposed to be measured.
Monkeyleg
Member.
With a yardstick.
Standing Wolf
Member in memoriam
Center to center is correct. Brownells and other shooting supply houses sell plugs to push into bullet holes in targets. It's the easy way to determine whether a hole touches or doesn't touch a ring, and makes center to center measurements a little easier and more accurate.
P95Carry
Moderator Emeritus
I'm not doubting that ''center to center'' is the way to go but .. always measure mine ''outside edge - to outside edge'' .... makes me try harder!
Anyways ... ain't got the gauges!
Why is it, in a 5 shot string ... there's always one bugger that wants to go it's own way!
Anyways ... ain't got the gauges!
Why is it, in a 5 shot string ... there's always one bugger that wants to go it's own way!
Center to center can be roughly or very closely achieved by measuring outside diameter with calipers and then subtracting one bullet diameter. If you are a gunwriter, pass go and throw out your two worst shots to "determine the gun's potential"
I think most agree that center to center of the two holes that are furthest apart is the right way. But measuring center to center isn't very accurate when small errors can mean the difference between first and second place. Some will advise measuring outside edge to outside edge and subtracting one bullet diameter. I usually measure from outside edge of one hole to the inside edge of the other. That eliminates the unnecessary math. That is, if one of the holes has a distinct inside edge, if both of them cut another bullet hole then the outside/outside/subtract method is required.
The hole gauges work very well. They will magnify the target rings and leave no doubt if a bullet is touching a ring or not. Interestingly, they often give a higher score than lower since the shooter will sometimes assume that a hole isn't touching a ring when, in fact, it is.
The hole gauges work very well. They will magnify the target rings and leave no doubt if a bullet is touching a ring or not. Interestingly, they often give a higher score than lower since the shooter will sometimes assume that a hole isn't touching a ring when, in fact, it is.
Pumpkinheaver
Member
What Navy Joe said.
Art Eatman
Moderator In Memoriam
Since the benchrest folks compete in terms of group size, I've always used their system: Center to center. Since I sorta grew up using that measurement, I've stayed with it.
Since that's the most commonly accepted method of measurement, it makes conversation easier. You don't have to explain to folks what you're talking about.
Art
Since that's the most commonly accepted method of measurement, it makes conversation easier. You don't have to explain to folks what you're talking about.
Art
Dorrin79
Member
Me too!
bogie
Member
I shoot benchrest. Competitively.
Say you're shooting a 6mm (.243). You have a hole in the paper that is a half inch at its longest portion. You take that 0.500" and subtract the diameter of your bullet (0.243") and you're there.
If you've got a half-inch hole with your .308, subtract .308.
Say you're shooting a 6mm (.243). You have a hole in the paper that is a half inch at its longest portion. You take that 0.500" and subtract the diameter of your bullet (0.243") and you're there.
If you've got a half-inch hole with your .308, subtract .308.
Hawk
Member
Regrettably, I measure my handgun group sizes by using a shotgun pattern target.
Currently, I'm "improved modified" and hope to reach "full" in the future.
Currently, I'm "improved modified" and hope to reach "full" in the future.
keyhole
Member
For casual shooting, if they all stay in the target, I figure that is was OK.
For the rest, if I can cover them with a hand, quarter, or something like that is accecptable.
For the rest, if I can cover them with a hand, quarter, or something like that is accecptable.
Drizzt
Member
lately, I've been using an odometer....
jhisaac1
Member
I'll bet someone can make a killing with a special custom designed/marked group measuring ruler marketed to shooters.
"The light must be playing tricks on you. Sure the group 'looks' pretty big, but according to my group measuring ruler here, it's less than an inch."
Jason
"The light must be playing tricks on you. Sure the group 'looks' pretty big, but according to my group measuring ruler here, it's less than an inch."
Jason
bogie
Member
There is one. Sinclair's sells it.
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