What do the ES and SD stand for in the 9mm tests mean?

BergmeierBergmeier New MemberPosts: 1 New Member


  • BigslugBigslug Senior Member Posts: 7,038 Senior Member
    Welcome! A reference to the 9mm tests in question would be helpful information, but in chronograph velocity testing they stand for "Extreme Spread" and "Standard Deviation"

    "Nothing is safe from stupid." - Zee
  • breamfisherbreamfisher Senior Member Posts: 13,101 Senior Member
    Extreme spread is the overall difference in the highest and lowest velocity tested.

    Standard deviation is a measure of how much each different shot's velocity differed from the overall average velocity.

    Both are measures of how similar in velocity each individual shot in a shot string is.
    Overkill is underrated.
  • NNNN Senior Member Posts: 23,967 Senior Member
    Bergmeier wrote: »
    Welcome aboard
    A Veteran is someone that served in the Military, it does not matter where they served.
  • N320AWN320AW Senior Member Posts: 648 Senior Member
    Bergmeier wrote: »

    Standard deviation? That's easy to explain. In case you have some idle time on your hands . . . here you go! :uhm:

  • TeachTeach Senior Member Posts: 18,412 Senior Member
    ES and SD- - - - -BS for ADD and OCD shooters!
    Hide and wail in terror, Eloi- - - -We Morlocks are on the hunt!
    ASK-HOLE Someone who asks for advice and always does something opposite
  • snake284snake284 Senior Member Posts: 21,851 Senior Member
    When I first got a Chronograph and was really balls to the wall into reloading, I worried about Standard Deviation and all that fancy crap. But for me now, I just go out and fire me a couple of 5 shot groups and note the individual velocities of each shot. To me, extreme spread is a more immediate indication my load has a problem.
    Daddy, what's an enabler?
    Son that's somebody with nothing to do with his time but keep me in trouble with mom.
Sign In or Register to comment.
Magazine Cover

GET THE MAGAZINE Subscribe & Save

Temporary Price Reduction


Give a Gift   |   Subscriber Services


GET THE NEWSLETTER Join the List and Never Miss a Thing.

Get the top Guns & Ammo stories delivered right to your inbox every week.