Groups measurements

[texasrimfirenut]

I am a fairly new member on here. I've been looking at a lot of groups that others shoot, to see how certain rifles/ammo combos are shooting.

On here is it standard to state the group sizes edge-to-edge or center-to-center? I am sure its get done both ways but wondering most of the time when I see a number like .321 or .534 and the such if those are ctc or an outside measurement.

 

[PinesAndProjectiles]

Center to center is most popular. Measure the outside diameter of the group and subtract one bullet diameter.

IE, if you shoot a group that's .44" measured to the outside edges of each of the bullet holes, subtract .22 for bullet diameter and it leaves you with a .22" group.

 

[texasrimfirenut]

Okay, great. That is what I have always done. Measure outside to outside with calipers and I have always subtracted .21 as then I check individual holes with my calipers is most often get .21

 

[PinesAndProjectiles]

Okay, great. That is what I have always done. Measure outside to outside with calipers and I have always subtracted .21 as then I check individual holes with my calipers is most often get .21

You're shorting yourself. The bullet is .22 in diameter....

 

[texasrimfirenut]

You're shorting yourself. The bullet is .22 in diameter....

Fantastic, my groups just got a little bit better then! LOL!

 

[barronian]

You're shorting yourself. The bullet is .22 in diameter....

but the hole that they make isnt ... @texasrimfirenut approach will give a more 'corrrect' result.

 

[PinesAndProjectiles]

but the hole that they make isnt ... @texasrimfirenut approach will give a more 'corrrect' result.

You're right. I forgot bullets shrink after they're fired.

 

[Antares]

If you haven't already, try the Ballistic-X app. Maybe it makes me lazy, but I love it.