Measuring Groups
#2
Join Date: Feb 2003
Location: Blissfield MI USA
Posts: 5,293
RE: Measuring Groups
with a gun you normally measure the outside of the group and then subtract the diameter of one bullet hole. With arrows I normally just measure the longest distance between arrows on the outside.
Paul
Paul
#8
RE: Measuring Groups
I always measure center to center too.
That way the value you end up with is not affected by the arrow diameter itself. It only mesures the difference in the points where the arrows impacted.
If 2 shooters can put their arrows's centers inside a 1 inch group, the one with the smaller diameter shafts will have the smalllest group if you measure the outside, even though both produced the same level of precision.
It's like shooting guns. A guy with a 22 could shoot poor groups, and stillhave smaller groups thana guy with a 45 that shoots better if you measure the outside. On the other hand, the 45 is more likely to score higher on a target and hit more tissue on an animal.
For actual group size, you want the center-to-center number.
The easiest way to measure it, assuming you want more than eyeball accuracy, is to combine what Zak and Paul said. Measure the outside of the group with a caliper, and then subtract one bullet diameter to calculate the center-to-center.
That way the value you end up with is not affected by the arrow diameter itself. It only mesures the difference in the points where the arrows impacted.
If 2 shooters can put their arrows's centers inside a 1 inch group, the one with the smaller diameter shafts will have the smalllest group if you measure the outside, even though both produced the same level of precision.
It's like shooting guns. A guy with a 22 could shoot poor groups, and stillhave smaller groups thana guy with a 45 that shoots better if you measure the outside. On the other hand, the 45 is more likely to score higher on a target and hit more tissue on an animal.
For actual group size, you want the center-to-center number.
The easiest way to measure it, assuming you want more than eyeball accuracy, is to combine what Zak and Paul said. Measure the outside of the group with a caliper, and then subtract one bullet diameter to calculate the center-to-center.