1000yrd E.S. S.D. ?????????

[LongRanger]

Mark Scronce speaks of what he knows. He, as a winning benchrest shooter, will... along with many long range shooters ... grind you up into dog food if you think SD is the queen of velocity statistics. ES is what counts, especially for a LR shooter.

There is just no way a shooter can take a calculated statistical result such as SD and work with it to improve a load. You would certainly have to go back to the individual shot results to gain knowledge of changes needed. SD does not tell you the best nor the worst about a string of shots. It is a confidence factor that tells you if you change NOTHING you could with some degree of certainty expect the same SD the next time....or that, if you knew the extreme high and low of a series of velocities, you could expect a certain percentage of them to fall within a certain range.

While a single digit ES, proven by a significant number of shots, will tell us our load is as consistent as it is going to get, a single digit SD might look and sound good but the devil is in the details. You might have such a SD resulting from a super string of 100 shots with hardly any velocity difference.....except for 3 or 4 shots that were 15 fps faster/slower than the average.

ES tells us Whoa! Here's a nice string of similar velocities But here is a shot 15 fps faster than the average of the main group and here are 3 that are 15 fps slower and that will take me out of the x ring if I don't do something about it.

Get your ES into single digits and the low SD will follow. The reverse is not necessarily true.

Of course, neither low ES nor low SD mean the load is accurate.

Frank

 

[JHardy]

Frank:

Well said.

Jim

 

[Rtheurer]

You know how it goes: you get the unexplained shot and you adjust or not. Then you wait for the target to come back up out of the pits and pray the spotter is centered. We all know that feeling.

Thanks again,
Jim[/QUOTE]


Jim

I dont see this happening to you very often. You have the best equipment and Ammo on the line. You are sooooo easy to coach. I really enjoy that when a shooter comes to the line with a the skills and a rifle that can hold 1/2 MOA at 1000 yards. Take note Young apprentice. This topic is one of Jims favorite's. He lives breaths and eats single digit ES. After seeing the results on Paper I have to say Im a believer.

'Load and be ready' 'Give me and X @ 3:00'

Russ T

 

[memilanuk]

Jim,

I've heard a few people mention your tight vertical during shot strings; I believe a while back on another forum you mentioned that there were a few simple things that you considered key to minimizing ES/SD/whatever metric a person chooses.

Perhaps we could get you to expound on those points? I know I try to cover all,or at least 'most') of the bases that I think are important/useful in my loading, but it may be informative to hear how you approach things.

Monte

 

[300ulta210]

LongRanger Said, low ES nor low SD means a load is accurate. that statement has me scraching my head, I would think if I had a load that had lets say, an E.S. of 10 then my S.D. should be low to and that load should have been an accurate load . Is this not always the case with you guys? I have only shot out to 800 and 1000 yrds a few times what I noticed on my target was, I would have a shot jump up on the target and a round or two later I would have a shot drop low this is after I had my elevation dialed in. This is what I want to eliminate.

 

[halfmoanut]

I am curious to know how do you tune your rifle at 1000yds,do you have a guy spotting your flags that have to be very high in the air where your bullet is traveling.I tune my rifle at 200-300 where I can read the conditions thru wind flags I find that conditions rule the bullets flight more than any other factor and wind direction will also make bullets go higher or lower.Can someone let me know how to tune a 1000yd rig correctly?I have no problem with believing es &sd contribute to consistency in accuracy.But can't wind also be a factor for vertical in a group along with sunlight and clouds etc,etc.

 

[memilanuk]

do you have a guy spotting your flags that have to be very high in the air where your bullet is traveling.

How high do you think that bullet is traveling above the LOS en route to the target @ 1k?

But can't wind also be a factor for vertical in a group along with sunlight and clouds etc,etc.

Oh, most definitely. There are ranges that will absolutley drive you to drinking with the vertical twitchiness - and its not always easily visible,flags not in the right spot, etc.) to the shooter, other than having the same load out of the same gun throw shots high or low at one range/location but not at another.

 

[RDavies]

Just to throw another question into the mix, how about if you get a realy low ES, but the velocity is right inbetween 2 nodes? Results on the target might work better to go to to a slightly higher ES, but have the velocity right in the middle of a node. Unless you have a tuner, then you can have both. Would you agree with this?

 

[jb1000br]

Don't sweat the chronograph numbers so much...put it on paper---> http://www.6mmbr.com/laddertest.html

JB

 

[JHardy]

What Jason said. He does most of his testing at 1025 yards. When he gets his vertical,the name of the game) to 2' at that distance, he is dangerous. In short, Jason is the very best at load development I have ever seen. Period. He does chrono testing, but the way he tests, the ultimate numbers are on the target.

Jason's article on Load Development should be downloaded by every shooter interested in long range accuracy. Heck, I have it as a shortcut on my desk top, and I have printed out the entire article for reference. IMHO, it is the definitive source on the subject.

A few years ago, I sent Jason 58 106 grain Clinch River 6mm bullets,meplats closed) to test in his 6BR light gun -- because I knew,even then) that he was the best at load development. In short, it was that testing that completely opened the door to people understanding what closing the meplat can do. I don't think I am mistaken in saying that it was Jason's test with those bullets that got the attention of Bryan Linz -- and that is a pretty good bench mark.

Jim Hardy

 

[memilanuk]

While I agree that is a *very* good article... many people don't have ready access to a 1000yd range for testing. There are far more 500/600yd ranges in this country than 1000yd, and mot folks have to make do with local ranges in the 100-300yd size. Driving hours to a 1000yd range to do load testing in the wee hours of the morning or late in the evening - and hoping that the weather cooperates - simply isn't feasible for everyone.

For those who are so fortunate - I envy you.

 

[Mark Walker in TX]

Is it possible to gather good load info while shooting 3 shot groups over the chronograph? For instance last sat. I ended up with an E.S. of 4.30 and a S.D. of 2.00 keep in mind this was a three shot group. Am I wasting my time with 3 shot strings or should I bump it up to five or just go ahead and shoot 10 shot strings? ANOTHER WORDS If I load 10 rounds would my E.S. be different then or would it still read 4.30?

When measuring ES/SD, you need to be shooting at least strings of 10.

 

[JHardy]

Monte:

You can do Jason's load development at almost any distance. At 300 to 600 you can get it done. But as you know already, you have to verify that load at the distance you are shooting in competition.

I am with you all the way in saying that folks that can do all their testing at 1000 are blessed. It always seems that those who are so blessed and also blessed in the 1000 yd matches.

Truth be known, most of my 'shooting' involves nightly goal-oriented dry fire sessions in my basement. Most of my low ES comes from the loading bench in my shop. So, I understand. What a dream to have your own 1000 yd range or the same close by.

BTW Monte, good luck at Butner this year. I ASSUME you are shooting FTR -- you could take it all.

Jim