« previous next »
Pages: [1]   Go Down

Author Topic: Measuring Groups  (Read 1081 times)

0 Members and 1 Guest are viewing this topic.

Offline TScottO

  • Trade Count: (2)
  • A Real Regular
  • ****
  • Posts: 778
Measuring Groups
« on: March 13, 2003, 01:48:00 PM »
I would like to know how everyone measures their groups. Do you measure your best groups from the best shooting hole in your cylinder or do you measure your groups from all 5 or 6 shots in your cylinder? As far as actual group measurements go, what method do you use? I want to be on the same page as everyone else when it comes to group measuring. I simply take the two farthest bullet holes and measure the distance center-centerÂ… this is my groupÂ… i.e. the smallest circle that will surround every shot.

Thanks,
Scott
Logged

Offline KN

  • Trade Count: (0)
  • Senior Member
  • *****
  • Posts: 1962
Measuring Groups
« Reply #1 on: March 13, 2003, 03:18:55 PM »
Thats the way to do it, center to center farthest apart.  KN
Logged

Offline CJ

  • Trade Count: (3)
  • Contributor
  • ***
  • Posts: 294
Measuring Groups
« Reply #2 on: March 14, 2003, 03:20:20 AM »
If you measure inside edge to outside edge of the farthest two you get the same result without finding the exact centers.
Logged
NRA Lifer

Offline Mikey

  • GBO Supporter
  • Moderator
  • Trade Count: (2)
  • Senior Member
  • *****
  • Posts: 8734
Measuring groups
« Reply #3 on: March 14, 2003, 04:05:26 AM »
TScott0:  there are three ways to measure groups:  (1) center to center of the largest group;  or, if you are like me and need to lie a lot, (2) center to center of the two closest shots; or, if you are also like me and need a bunch of encouragement (3) the high five goes to the group with the best lookin' babes in it.  Mikey.
Logged

Offline Gregory

  • Trade Count: (0)
  • Senior Member
  • *****
  • Posts: 1482
  • Gender: Male
Measuring Groups
« Reply #4 on: March 14, 2003, 07:10:44 AM »
Quote from: CJ
If you measure inside edge to outside edge of the farthest two you get the same result without finding the exact centers.


I measure the same as CJ.  I use 6 shot groups for revolvers, one out of each cylinder.  I'll use 3 shot groups out of my single shots for preliminary load development and then go to five shot groups to fine tune.
Logged
Greg

NRA Endowment Life Member
the right of the people to keep and bear arms shall not be infringed.
Second Amendment, U.S. Constitution (1791)

Offline thomas

  • Trade Count: (0)
  • Avid Poster
  • **
  • Posts: 159
Straight from the rule book
« Reply #5 on: March 14, 2003, 12:55:11 PM »
Groups are to be measured by any method approved by the NBRSA  in  .001  inch.    The  Sweany  Type  Reticle  Rule  (or  its  equivalent)  will  be  the  only  official measuring device used at all Registered Matches.  In measuring groups fired with calibers larger than .22 (unless the Reticle is calibrated for the caliber to be measured) the measurement shall be made from the extreme outside edges of the 2 widest bullet holes and the actual differential of the larger calibers shall be subtracted  from  the  measurement  read  on  the  measuring  scale.
Tom
Logged

Offline Bullseye

  • Trade Count: (9)
  • Senior Member
  • *****
  • Posts: 1879
Measuring Groups
« Reply #6 on: March 14, 2003, 05:06:54 PM »
Unless I am developing a load, I just look at it as say "Thats a good group".  Or " Man that is a teriible group".
Logged

Offline helobill

  • Trade Count: (0)
  • Contributor
  • ***
  • Posts: 289
Measuring Groups
« Reply #7 on: March 14, 2003, 05:07:53 PM »
Thomas,
Sounds like the "rules according to Hoyle"...tell me you copied that out of something :grin:  I don't have a Sweany reticle so I just use a pair of calipers. Load 6, shoot all 6 slow fire, measure, 'cause that's the way I shoot when I hunt. Had an old revolver that would always throw one high out of the same cylinder, I'd leave that one empty when I went hunting. My SRH 44 groups pretty well, no matter which cylinder starts the party.
Helicopter Bill
Logged

Offline thomas

  • Trade Count: (0)
  • Avid Poster
  • **
  • Posts: 159
All it is saying.
« Reply #8 on: March 15, 2003, 08:09:39 AM »
Is you measure the widest part of your group and subtract the bullet dia.
It is the ONLY way groups have ever been measured in Competion where group size is the goal.
the use the sweany to keep it consistant with other clubs.
This is the way a group will be measured by VV or SSK or anyone else guaranteeing their barrel or gun will shoot SUB MIN of ANGLE.
Tom
Logged

Offline Cabin4

  • Avery H. Wallace
  • GBO Supporter
  • Trade Count: (2)
  • Senior Member
  • *****
  • Posts: 4938
  • Gender: Male
  • Out West
Measuring Groups
« Reply #9 on: July 05, 2003, 03:28:21 AM »
What if you shot 3 times and had 2 holes touching and one 3 inches out from the furthest of the first 2 shots ?  

Do you use any averaging or is it a 3 inch group ?
Logged
Avery Hayden Wallace
Obama Administration: A corrupt criminal enterprise of bold face liars.
The States formed the Union. The Union did not form the States. States Rights!
GET US OUT OF THE UN. NO ONE WORLD GOVERNMENT!
S.A.S.S/NRA Life Member/2nd Amendment Foundation
CCRKBA/Gun Owners of America
California Rifle & Pistol Association
Ron Paul Was Right!
Long Live the King! #3

Offline Ka6otm

  • Trade Count: (0)
  • Avid Poster
  • **
  • Posts: 241
Measuring Groups
« Reply #10 on: July 05, 2003, 04:53:03 AM »
cabin4,

If you were a writer for one of the gun magazines, it would be a sub MOA group with a called flier.

If you were honest with yourself and others, it would be a 3 inch group.

Ka6otm
Logged

Offline Lloyd Smale

  • Moderators
  • Trade Count: (32)
  • Senior Member
  • *****
  • Posts: 18267
Measuring Groups
« Reply #11 on: July 05, 2003, 09:50:38 AM »
What I do is fire a 12 shot group from a relvolver and allow myself to throw out one flyer. I usually do this 3 times for each load and average the results.
Logged
blue lives matter

Offline Cabin4

  • Avery H. Wallace
  • GBO Supporter
  • Trade Count: (2)
  • Senior Member
  • *****
  • Posts: 4938
  • Gender: Male
  • Out West
Measuring Groups
« Reply #12 on: July 06, 2003, 01:06:37 AM »
When using sand bags and not being a totally accomplished expert shooter, is is fair to assume the occasionla flyer is me or the rifle ?

I don't know the answer here but it does seem to be a very critical measurement in a non-competitive enviroment for it to be a 3 inch group.

For non-competative measuring, using sand bags off a bench, is thier any "giving" for the inaccuracies of the shoooter or the bench set-up ?
Logged
Avery Hayden Wallace
Obama Administration: A corrupt criminal enterprise of bold face liars.
The States formed the Union. The Union did not form the States. States Rights!
GET US OUT OF THE UN. NO ONE WORLD GOVERNMENT!
S.A.S.S/NRA Life Member/2nd Amendment Foundation
CCRKBA/Gun Owners of America
California Rifle & Pistol Association
Ron Paul Was Right!
Long Live the King! #3

Offline Bullseye

  • Trade Count: (9)
  • Senior Member
  • *****
  • Posts: 1879
Measuring Groups
« Reply #13 on: July 06, 2003, 12:15:07 PM »
Been thinking about this thing this weekend.  I was testing some loads for my 30-30 Contender.  Best load combo gave me a 2 1/2" 5 shot group, but three of the shots were touching.  Not sure what this tells me, but here is what I think.  Since I was shooting at a less than perfect bench resting the front of the gun and holding the back this load seems pretty good.  If the load was not decent, I do not see how three of the 5 could be touching.  I assume the fliers were me.  I would like to see all 5 touching, but that did not happen.

So what do you all think?  Is it a good load or not?
Logged
Pages: [1]   Go Up
« previous next »