Understanding Rifle Precision

By Dan Zimmerman

By David Bookstaber

When testing guns for accuracy it is common practice to look at the Extreme Spread of a group of 3 or 5 test shots. I will explain why this is a statistically bad measure on a statistically weak sample. Then I will explain why serious shooters and statisticians look instead at some variation of circular error probable (CEP) when assessing precision . . .

It is easy to fool yourself with Extreme Spread…and even easier to fool others. First, note that even the most precise rail gun will occasionally print a “flier.” If 99 out of …read more

Via:: Truth About Guns