Scoring question??

[nightfighter]

Can someone explain to me why groups are measured center to center?

Frankly I don't feel comfortable with the idea that the measurement is smaller than the actual hole in the paper.

I'm sure there must be a reason, but I don't know what that might be.

Thanks,

NF

[Dwight Pilkilton]

Scoring center to center is more accurate only if you have the right equipment to do it. you need a optical device especially designed for this task, other wise you need to measure outside to outside and subtract the bullet diameter. the holes in paper are a bit self healing and tend to close up to a smaller diameter than the actual bullet diameter, for a good visual on this try using a scoring plug on a single shot on paper and see how big the real bullet hole is....most folks fear the scoring plug...but it has saved my butt more than a few times shooting 3-P CMP Sporter.

Dwight P

[nightfighter]

Thanks Dwight, I appreciate the explanation.

When measuring OTO, do you then include the dark ring around the hole?

NF

[Dwight Pilkilton]

I do as this is a pretty good indication of where the bullet hole is, I also look very closely at the tiny tears in the paper and see how far they run out. A scoring plug is $5 and a good investment to get an accurate (bad pun) picture on the actual bullet hole size.

Dwight P

Good question BTW, we have resident national Champions here on this board that know far more about this than I do, perhaps they will chime in or even write us a little post on measuring groups

[Scotty]

if you tried to compare groups from two rifles , say a 6mm and a 308, youd have an incorrect comparison in favor of the 6mm unless you measured center to center, because the 308 bullet is wider edge to edge.

also some same diameter bullets of different types make different size holes in paper[ eley holes look bigger than sk holes]
the plug keeps you scoring an equal distance from center on both.

scotty

[nightfighter]

That makes a lot of sense, thank you both.

NF