What are your standards when working up a load?
Acceptable extreme spread and standard Deviation numbers?
Acceptable extreme spread and standard Deviation numbers?
-
If you are having trouble with your password change please click here for help.
Acceptable ES and SD
- Thread starter alexs2006
- Start date
That doesn’t answer my question. I asked what is your acceptable range.
I have an SD of 5.2 with an ES of 15.1. So I’m trying to guage if that is good or if I need to improve
What brand of chrony are you using?
Most models can exhibit up to 0.5% error, so for a rifle bullet at 2800 fps could have an instrumentation error of +/- 14 fps before you even get started. In practice, I've seen most reported with better precision than that, but at rifle velocities, that error will be a factor in your results.
Most models can exhibit up to 0.5% error, so for a rifle bullet at 2800 fps could have an instrumentation error of +/- 14 fps before you even get started. In practice, I've seen most reported with better precision than that, but at rifle velocities, that error will be a factor in your results.
@stainlineho
Garmin Xero C1 Pro
Garmin Xero C1 Pro
I’m going to load up 10 rounds of each and test again to see what that data reveals. If it’s repeatable I’ve found my loads to tweak on with searching depth
How big is your sample size?
Single digit SD is more than good enough for nearly every rifle application. Decent factory ammo is usually in the teens for an SD for 15-20 shots.
Your velocity is also a factor relative to distance and target size as well. You can adjust the velocity for your high and low number and see what kind of data difference it makes, and apply that to target size and you'll know if it's good enough.
That being said I've won plenty of matches and hit alot of targets with an SD of 15-18.
Single digit SD is more than good enough for nearly every rifle application. Decent factory ammo is usually in the teens for an SD for 15-20 shots.
Your velocity is also a factor relative to distance and target size as well. You can adjust the velocity for your high and low number and see what kind of data difference it makes, and apply that to target size and you'll know if it's good enough.
That being said I've won plenty of matches and hit alot of targets with an SD of 15-18.
These numbers I posted is a 5 shot sample size. I’m going to load 10 rounds of each load to see if I can duplicate the numbers.
So it sounds like if ES and SD are under 20 is more than acceptable
