Proper shot group measurement ??

[270fan]

How should shot groups be measured ..... is it center of hole to center of hole? Thanks.

 

[mag41vance]

How should shot groups be measured ..... is it center of hole to center of hole? Thanks.

Measure the overall outside edges of your group, then subtract the bullet diameter, and that will give you the center to center grouping.

 

[JD338]

How should shot groups be measured ..... is it center of hole to center of hole? Thanks.

Measure the overall outside edges of your group, then subtract the bullet diameter, and that will give you the center to center grouping.

Exactly!
Thanks mag41vance.

JD338

 

[270fan]

Thanks fellas. Thought that was right. Now.... if I can just put them all in one hole I won't have to do any measuring.

 

[phutch30]

So If for example of my group measures .750 largest edge to edge I would then subtract .284 for a 7mm, which would result in a group size of .466. Correct?

 

[Tiny]

So If for example of my group measures .750 largest edge to edge I would then subtract .284 for a 7mm, which would result in a group size of .466. Correct?

Yep.

 

[phutch30]

Interesting, all this time I have been short changing my rifle/load combo.

 

[USMCDM24]

I've always measured center-to-center as well and have been short-changing myself too. I've found that it actually takes about .015 off your group measuring outside-to-outside & subtracting bullet diameter. I guess that's pretty reasonable (& more accurate) seeing as locating the "true" center of the hole is usually best guess.

 

[FOTIS]

I've always measured center-to-center as well and have been short-changing myself too. I've found that it actually takes about .015 off your group measuring outside-to-outside & subtracting bullet diameter. I guess that's pretty reasonable (& more accurate) seeing as locating the "true" center of the hole is usually best guess.

Right on!

 

[270fan]

How can measuring from outer edge to outer edge and subtracting the bullet diameter be more accurate than measuring center of hole to center of hole? Doesn't make sense to me. Thanks. ABC

 

[FOTIS]

How can measuring from outer edge to outer edge and subtracting the bullet diameter be more accurate than measuring center of hole to center of hole? Doesn't make sense to me. Thanks. ABC

How do you precisely find the center of the bullet hole ?