figuring out es

[Whatsquirrel]

I've done a search & can't find anything to show me how to figure out the es %. Playing around with my at44 long in .22 cal ran a string & got the following:
Jsb 18.1gr
975 200bar
973.3
973.9
978
973.6
979.9
978.8
980.6
979.2
973.3 160bar
980.8
982.2
976.5
973.8
971.4
966.6
966.5
961.6
960.4
953.4 140bar
Can someone please explain to me how to figure out the es? That way I will knkw how to do it in the future. In the shot stri g I would probably just shoot to shot 15. That's 1.5 clips at only a 10.8 fps spread. Thanks guys.

[Bullit]

ES "Extreme Spread", means that it's the difference in readings, between the highest and the lowest readings, from the shots you have measured.   
If you shoot 10 shots and the highest is 975fps, and the lowest is 925fps,,, then your extreme spread (ES) is 50 fps.   
Hope this helps.

[Bwalton]

Do not touch it! that is an awesome Es! you at 1% That is all you need! Myself when hunting I shoot one clip. If you were to stop at 10 shots you would have an avg of 976.56fps @38.5ftlb and a ES of 7.3! your 100yard groups would be crazy good. Thats better then any regulated gun! Then you would have extra shoots without poi change if needed.

[rsterne]

A 10.8 fps ES in that string is 10.8 / 982.2 =  1.1%.... You can accept a wider ES the closer your target is.... At 50 yards, you want all the shots to be within 4% or less, at 75 yards 3% and 100 yards 2%.... At 25 yards an 8-10% ES is likely acceptable for most situations.... You can figure what the lowest acceptable velocity is by deducting the ES you want from 100% and multiplying your highest velocity by that number.... For an ES of 4%, you would use 100 - 4 = 96% so with your highest velocity of 982.2 fps, multiply by 0.96 to get 942.6 fps.... In other words, your entire string is well within a 4% ES, and in fact if you reduce your hammer strike somewhat so that the first shot is 3-4% below the (now lower) peak you will get even more shots within that 4% ES....

Bob

[Whatsquirrel]

Do not touch it! that is an awesome Es! you at 1% That is all you need! Myself when hunting I shoot one clip. If you were to stop at 10 shots you would have an avg of 976.56fps @38.5ftlb and a ES of 7.3! your 100yard groups would be crazy good. Thats better then any regulated gun! Then you would have extra shoots without poi change if needed.

I thought it was pretty good. I'm gonna pull the hammer back out & lock the hammer adjuster down where it's at & just leave it alone. I'm looking into getting a bt65. Just not sure if I want it .22 or .25 cal. Thanks for the input.  Now on to the AT44w in .177 see what we can do with it.