Long Range Hunting Online Magazine Correct way to measure a group?
 Home LRH Store Forums Long Range Rifles Articles Reviews Video G7 Ballistics Calculator Rules & FAQ Register Search Today's Posts Mark Forums Read

# Correct way to measure a group?

#1
10-17-2005, 02:52 AM
 Silver Member Join Date: Mar 2005 Location: Australia Posts: 177
Correct way to measure a group?

What is the correct way to measure a group centre to centre?
Can someone post a picture example of measuring a group using verniers, would be appreciated.

Thanks

Cheers
__________________
skip
#2
10-17-2005, 07:41 AM
 Gold Member Join Date: Oct 2004 Location: Northamptonshire England Posts: 675
Re: Correct way to measure a group?

Skip,
From an ex benchrest shooter:
Identify the edges of your group that are furthest apart and draw a line through the centre of the opposing bullet holes. Set your Vernier on the group so that the edges of the blade form a 90 degree angle with the scribed line at the furthermost edge and take a reading.
If you want to, divide by 1.09 to get MOA.
Hope the pix will help explain.

My 243 Group.

308 Group

Ian.

"I meant to shoot the pike but the duck got in the way"
#3
10-17-2005, 09:48 AM
 Silver Member Join Date: May 2005 Location: Bozeman, MT Posts: 239
Re: Correct way to measure a group?

I am far from an expert on this subject, but I'm sure that I have read that the holes left in paper targets are usually a little bit smaller than the caliber size. If this were true, it would make groups measured using this method prone to being slightly smaller than they actually are. The amount of effect this would have on relative group size (that is percentage) should increase as the group size decreaes. That is, on a 2" group a .1" error would make much less difference than on a .2" group. I've heard of actually measureing the centers of the bullet holes, however, I don't know of any superior way to do this.
__________________
Empirical results rule!
#4
10-19-2005, 02:01 AM
 Silver Member Join Date: Jan 2004 Location: Mississippi Posts: 181
Re: Correct way to measure a group?

I measure outside to outside on the farthest bullet holes, then subtract the bullet diameter. This will give the same result as measuring center to center.
#5
10-19-2005, 02:03 AM
 Silver Member Join Date: Mar 2005 Location: Australia Posts: 177
Re: Correct way to measure a group?

Thanks all, now I know how to do it 'properly'

Cheers
__________________
skip
#6
10-19-2005, 09:53 AM
 Silver Member Join Date: Mar 2002 Location: Prince George British Columbia Posts: 129
Re: Correct way to measure a group?

Now that depends also on where you are when the group is discussed. In comp. and at the range we measure the group outside to outside then subtract caliber. Later when talking about group sizes in the bar knocking back some cold ones the usual accepted practise is to automaticly eliminate the flyer, measure the remaining bullets then subtract the largest caliber you have at home. Also dont forget that the distance the group was shot at must be multiplied by 1.5
#7
10-19-2005, 10:10 AM
 Platinum Member Join Date: Jun 2001 Location: Potomac River Posts: 5,048
Re: Correct way to measure a group?

One thing that will help your group size is to take your target to work and put it in the copying machine and set the machine for 50% reduction. [img]/ubbthreads/images/graemlins/grin.gif[/img] Sometimes, if I am having a bad day I have to use more than 50% reduction [img]/ubbthreads/images/graemlins/blush.gif[/img]
__________________
The Smokin Fur Rifle Club

 Bookmarks

 Thread Tools Display Modes Linear Mode

 Similar Threads for: Correct way to measure a group? Thread Thread Starter Forum Replies Last Post afp1 Reloading Equipment and Components 13 01-16-2012 03:42 PM zookman Long Range Hunting & Shooting 21 02-07-2011 09:54 AM Down Under Hunter Rifles, Bullets, Barrels and Ballistics 0 12-07-2008 06:03 PM Swift One Reloading 3 01-19-2007 10:23 AM Dave King Reloading 15 01-21-2006 08:26 AM

 Current Poll Do you wear hearing protection while hunting? Usually do Usually do not No but I probably will in future
 Current Poll - 2 Do you have a high speed Internet connection? Yes, DSL, satellite, wireless or something else. - 89.17% No, only dialup right now. - 10.83% Total Votes: 3,038You may not vote on this poll.

All times are GMT -5. The time now is 02:16 AM.