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Posted By: salmonhead Measuring group size? - 09/09/17
Just to be on the same track here, what is the standard way to measure a group? Assuming its the nice triangle of three shots, what method do you all use? Measure the distance from the furthest out bullet to the line between the other two or measure between bullet to bullet and average or what? For comparison sake while developing loads, i kind of want something that is an honest representation and repeatable to quantify the good from the bad on loads.
And as a side note, anyone have a good reason why some loads print two stacked and there is always a flier an inch or two out? Some loads do it, some dont?
Posted By: JohnChilds Re: Measuring group size? - 09/09/17
Measure the distance to the outside edges for the furthest two shots, and then subtract the bullet diameter.
Posted By: salmonhead Re: Measuring group size? - 09/09/17
ok. got it. Thanks.
Posted By: mathman Re: Measuring group size? - 09/09/17
Originally Posted by JohnChilds
Measure the distance to the outside edges for the furthest two shots, and then subtract the bullet diameter.


This method usually underestimates the group size a bit.
Posted By: Steelhead Re: Measuring group size? - 09/09/17
Copenhagen can
Posted By: JohnChilds Re: Measuring group size? - 09/09/17
Mathman, I would agree if you measure to the outside of the actual hole. I measure to the outside of the carbon ring, which I think approximates the outside edge of where the bullet passed through the target.
Yard stick...
Posted By: mathman Re: Measuring group size? - 09/09/17
Originally Posted by JohnChilds
Mathman, I would agree if you measure to the outside of the actual hole. I measure to the outside of the carbon ring, which I think approximates the outside edge of where the bullet passed through the target.


The smudge usually isn't big enough either.
For groups over about a half of an inch I find it easier and quick to determine which two holes are the furthest apart, then measure from the outside edge of one to the inside edge of the other.

With one ragged hole the measure of the widest part, minus the bullet diameter is about the only good way to do it. I don't have to worry about many of those, though.
Posted By: Pharmseller Re: Measuring group size? - 09/10/17
Originally Posted by bsa1917hunter
Yard stick...



Gps





P
Posted By: Prwlr Re: Measuring group size? - 09/10/17
I use an app called On Target, available for free. The app has a list of bullet diameters. Scan the target, choose the diameter bullet, center the target circle (circle of bullet diameter size) on each bullet hole and read the size of the group on the Rt side in inches or MOA. Works very easily. It's possible to even keep a record of all scanned targets. It also computes distance to center of group and other vital stats. You can also input the POA and it will compute the vertical and horizontal distance of the group center from the POA.


I acquired it for free a couple of years ago, but haven't checked recently for availability, upgrades or cost.
Posted By: GuideGun Re: Measuring group size? - 09/10/17
Range Buddy is another free app available. A quick demo it seemed to work fairly well.

Worth a look
Posted By: Swifty52 Re: Measuring group size? - 09/10/17
On target is now shareware. 15 days usage for free, 11.99 to keep using it. They also added TDS program for 34.99.
https://ontargetshooting.com/
Posted By: Prwlr Re: Measuring group size? - 09/10/17
Thanks Swifty52.
Posted By: Azar Re: Measuring group size? - 09/11/17
I just purchased OnTarget Precision Calculator v2.25 last night for $11.99 (the free version v1.10 is no longer available). You get a 15 day trial and it works pretty slick. It's a bargain at $12. I love shooting, but I hate measuring targets.
Posted By: Hastings Re: Measuring group size? - 09/11/17
First you throw away all the targets with big groups
Posted By: Prwlr Re: Measuring group size? - 09/11/17
Originally Posted by Hastings
First you throw away all the targets with big groups


I keep a record of all loads/groups sizes along with wind and temp data on a form. I don't trust my memory. But do not keep the targets.
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