What is considered an acceptable ES an SD??

[Raptor]

I was just wondering what is considered to be an "Acceptable" number for your extreme spread and standard deveation?? I understand it should be as low as possible but was wondering what is considered to be the standard spread for 1000yd shooting. Thanks guys!!!!

 

[NeilNE]

Most 1K BR shooter like under 10.

 

[Rtheurer]

Raptor

You stillworking on your SuperX??? For prone NRA target with a 1 MOA X ring I like no more than 25fps ES out of 10 rounds. Ill ussually shoot it at distance to see how it holds elevation there and if the both look good, then away we go. If I was shooting the F class target I might be a bit more tighter on my expectations.

RT

This is after the brass has been fire formed a couple of times!

 

[Hammer]

... A 5-shot string is not a factual mathematical deviation equation.

Agree that larger sample sizes are better.

But don't understand that last statement.

 

[Raptor]

Thanks guys!! I was just needing an idea of where I needed to be.

Rtheurer,
Yes, I am still working on the SuperX. I don't know if you read my post to Robert or not but I did some long range shooting with it this weekend. I just shot mostly 3 shot groups because thats what I normally use for my long range practice. That will tell me where I am for wind call and elevation and also I can tell if me and the gun are shooting good that day. I do mostly tactical shooting where we are usually only required to hit a target a couple of times in a row. Plus it saves on barrels!!

I was getting 3 shot groups in the 1" to 1.6 range @ 400yds and at 600ys they were in the 2 to 3" range. I did a 5 shot and it was like 3.2" with 4 in around a 1.5" @ 600 so I thought that was pretty good. Most of my vertical is around 1.5" at 600yds so I must be pretty good on my load. I am using 46.5grs of H1000 with a 105 Lapua.

 

[1shot]

Well I'll say what a lot of others are thinking:
"I knew that the lower the number was, the better the load I was testing was, I just didn't know what SD really meant, or how the number was arrived at.
Thanks Donovan!!
Lloyd

 

[mysticplayer]

I gave up data crunching my chronie info when I found that my chronie had a larger reading error then the values I was searching for. Pretty common for garden variety chronies to have a 1/2% reading error.

For a 3000fps, that's +/- 15fps,extreme spread 30fps) in equipment error alone. Throw in some operator error and changing light conditions and the data is useless to me.

Instead, I use my chronie to ensure I don't get into 'hero' territory and use paper to determine issues with vertical stringing.

I found that testing at 300m or yds, brought out all the stringing issues on a given load. Testing on calm days, I look for loads with 1/2" or under vertical in the group. That's .15 min. Max would be 1" or 0.3min.

Not worried if the load strings horizontally because that is likely wind. Ideally, the load will look like a sideways football with the point towards the windward direction. I aim dead center to reduce aiming dispersion.

I have yet to find a load that shot good at 300m/yds that didn't shoot well further.

Jerry

 

[1shot]

Donovan,
Thank you.
Lloyd

 

[mysticplayer]

Donovan, something that I have wondered about but could never measure due to chronie error.

If you take one case and put in the exact amount of powder, bullet, primer and fire several rds in a short space of time, how much velocity variation do you get?

Is the velocity the 'same'?

Jerry

 

[mysticplayer]

Thanks for the info. Very interesting. Certainly agrees with my thoughts but don't have the equipment to get data.

I found the further I tested, the better for observing vertical stringing. Testing at 100yds has had many loads look wonderful only to fall apart at LR. I can see how your Chronie data would be helpful to work with the targets.

Jerry