Rifle Accuracy

[hken]

I have a question about rifle accuracy. Often we hear people talk of 1" groups, 2" groups, etc.. My question is, how is a group measured? Is it the closest points on the shots (inside edge), the center of the shots, the diameter of the smallest circle that will cover the shots in the group (outside edge of the shots), etc.? What is the standard? Also, is there a standard for the number of shots in a group, 3?, 5?. Just curious. Thanks

 

[Plateau Hunter]

There are several common ways that it is done. The way I measure my own groups is to measure from outside edge to outside edge of the two bullet holes that are farthest apart and subtract the bullet diameter. That is good enough for my purposes. The benchresters undoubtedly have some more complicated system. Plateau Hunter

 

[Kimberman]

There are several common ways that it is done. The way I measure my own groups is to measure from outside edge to outside edge of the two bullet holes that are farthest apart and subtract the bullet diameter. That is good enough for my purposes. The benchresters undoubtedly have some more complicated system. Plateau Hunter

Thats how most people do it and how I do it as well. Some people measure from center to center of the furthest point.

 

[ewc]

Yep.

Out-to-out minus bullet diameter.

 

[Tiny]

All the above and 3 round groups work for me.

 

[Whelen Man]

If I can do it I measure inside edge to outside edge. If that's not possible I measure outside to outside and subtract bullet diameter. I do it that way because hole diameter doesn't always equal bullet diameter. The benchresters use a clear gauge with circles on a caliper which are matched to the bullet holes. One circle is put concentric with each hole and the diameter is read off the caliper.