Standard deviations!!,

davide montini

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Eh!!!.... to all the pro’s out there who reload and chrony there loads .....what is an acceptable sd...I know the lower the numbers the better ....but but say you get a nice group let’s say...7/8”..3/4”...or 19mm or smaller
And you get like say 32.6 for a sd !!!!
What are your thoughts on this and what would you do to get lower numbers say your shooting for 15 or lower for a standard devation??.
Thanks for you time and thoughts and help people
Davide
 
If this is your accuracy at 100, I would move to at least 200 with 300 being better. Readjust your ammo so that you group 7/8" at that distance... low vertical dispersion.

The ES/SD, sorts itself out.

Jerry
 
A low SD is better than a bigger one.

But due to bedding and harmonics, the load that shoots the smallest group at the distance that matters is the best. And it may not be the load with the lowest SD.

For target rifle I like the SD to be 10 or less.

308Win at 525 yards
RAIL GUN 308 AT 525.jpg
 

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As mentioned 100yds won’t tell you much , it’s to short to see the variation. Push out and that 3/4moa , 100 yard group becomes a 2moa or worse..

For what it’s worth I like my ES to be under 10 and my sd in the low singles
 
Lots of theories on this - Jerry and I differ markedly on this one. I look for good groups at 100 and an ES under 10 and low single SDs.

However, I have gone with a load that had better accuracy but worse stats (still under my requirements though).

Your sample size matters as well. 5 is OK, 10+ rounds is better.

Also, validating at distance is important.
 
A low SD is better than a bigger one.

But due to bedding and harmonics, the load that shoots the smallest group at the distance that matters is the best. And it may not be the load with the lowest SD.

For target rifle I like the SD to be 10 or less.

308Win at 525 yards
View attachment 179611

Damn that is a BIG wris####ch! That is at 525 yards? I'm not worthy enough to even pick up your empty casings. ;-) Good shooting!
 
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I did not shoot that group. Another Gun Nut did.

And I did not make the ammo. My son did, as part of a contract to make match ammo for someone.

Some of you have seen Gold Cross Match ammo around.

Came off a Dillon 650.

That is a 20 shot group.
 
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