So whats the real deal with all this ES/SD BS

[Alex Wheeler]

While perfect compensation can only occur at one distance how bad do you think a 2" tune at 1k will shoot at 600? Very well. Not always the other way around though. Thats why my advice is to tune at the longest distance you will shoot. About the only game I would get crazy over ES would be ELR. My most extreme example was a ladder I shot that put 3 shots into .8" at the low node and 4 shots into 1.9" at the high node. Each of those nodes had over 30 fps of ES for each group of shots. But in general 12-15 fps of ES into 1-2" of vertical is quite common. I dont know why it seems to work like this, but if I had to pick a load based on nothing but chrony data I would pick the 12-15 es load over the 3 es load 99% of the time.

 

[Bart B.]

While perfect compensation can only occur at one distance how bad do you think a 2" tune at 1k will shoot at 600?

If a barrel is tuned to shoot 2" groups at 1000, the group at about 600 will subtend much more than 2/10th MOA vertically. Maximum ordnate happens at 55 to 60 percent of target range. That's where the two trajectories have the greatest vertical separation

Sierra's software easily plots two trajectories for a given bullet at two muzzle velocities to show that.

 

[Lefty Trigger]

While perfect compensation can only occur at one distance how bad do you think a 2" tune at 1k will shoot at 600? Very well. Not always the other way around though. Thats why my advice is to tune at the longest distance you will shoot. About the only game I would get crazy over ES would be ELR. My most extreme example was a ladder I shot that put 3 shots into .8" at the low node and 4 shots into 1.9" at the high node. Each of those nodes had over 30 fps of ES for each group of shots. But in general 12-15 fps of ES into 1-2" of vertical is quite common. I dont know why it seems to work like this, but if I had to pick a load based on nothing but chrony data I would pick the 12-15 es load over the 3 es load 99% of the time.

This is good to hear as going back over my data and pictures of targets, I clearly passed over good loads because the "numbers" were not there. I would get a great group then dick with it trying to get the numbers to come in as well and screw it all up and get frustrated. I'm starting to believe this is why I have always had bad luck with varget and gave up on it, it always shot better with worse numbers if that makes since and I could never get good numbers AND grouping!! Damn I have been looking as this all wrong for several years.... now I fell like an idiot!

 

[Evan]

This is good to hear as going back over my data and pictures of targets, I clearly passed over good loads because the "numbers" were not there. I would get a great group then dick with it trying to get the numbers to come in as well and screw it all up and get frustrated. I'm starting to believe this is why I have always had bad luck with varget and gave up on it, it always shot better with worse numbers if that makes since and I could never get good numbers AND grouping!! Damn I have been looking as this all wrong for several years.... now I fell like an idiot!

Borescopes, concentricity/runout gauges, and chronographs are at the top of my list of misused and overemphasized equipment. Leave them on the shelf until you have a problem you're trying to diagnose. They should not be a part of load development.

 

[Ccrider]

I can tell if my loading process is consistent by variations in fps. Also, you can weed out stray pieces of brass. Other than that, I rely on the target to tell me what load is the best.

 

[JFrank]

This is good to hear as going back over my data and pictures of targets, I clearly passed over good loads because the "numbers" were not there. I would get a great group then dick with it trying to get the numbers to come in as well and screw it all up and get frustrated. I'm starting to believe this is why I have always had bad luck with varget and gave up on it, it always shot better with worse numbers if that makes since and I could never get good numbers AND grouping!! Damn I have been looking as this all wrong for several years.... now I fell like an idiot!

Do you plan on revisiting a couple loads that you passed up?

 

[normmatzen]

Congrats to all of you folks. This is one of the most useful threads I have read on the Forum for a long time!

I shoot long range bench rest and characterize each new barrel for best ES for five, five shot groups done in round robin. This finds the load with least ES. This tunes the load for the first of the two dominant resonances of the barrel, the longitudinal resonance and is similar to a simple organ pipe resonance.
Then, I shoot at 1000 yd with 3 shot groups with one nominal load, one 0.5 to 1 % high and one low. I then adjust my tuner for best vertical dispersion. This is the cantilever resonance. This is the resonance where the barrel whips up and down a bit and correct tuning gives best positive compensation.
Now, I have a load that has low ES so the positive compensation only has to deal with a tight ES as we have already tuned the load for minimum Velocity variations. Then I find the accuracy when shooting 600 yd is still good.

And, yes, I do pretty well at long range bench rest, but I still suffer from trigger puller problems some time!!

 

[JFrank]

Norm
That’s gonna take me awhile to translate into( Farm Boy ) English, but let me ask you what you call side to side Barrel whip if up and down is cantilever resonance?

 

[simo hayha]

Side to side barrel whip. Is called 'dog tail' resonance.....

 

[JFrank]

Side to side barrel whip. Is called 'dog tail' resonance.....

Your kidding right ?

 

[Lefty Trigger]

Do you plan on revisiting a couple loads that you passed up?

Absolutely! Going through data and targets and looking for loads that grouped well but had "sorta" good numbers but passed over. I have found a few worth retesting, some are kinda slow but shot great and a few are faster.

 

[JFrank]

Absolutely! Going through data and targets and looking for loads that grouped well but had "sorta" good numbers but passed over. I have found a few worth retesting, some are kinda slow but shot great and a few are faster.

The high nodes are really fun, they’ll take ya to nirvana then break your heart but just like a bad girlfriend ya keep going back

 

[Lefty Trigger]

Here's a varget test that I completely tossed out because I could not shift the loads and get decent numbers (single digit ES numbers) but 28.5gr and 29.4gr load showed potential. It's one I'm going to retest for sure...

 

[JFrank]

Here's a varget test that I completely tossed out because I could not shift the loads and get decent numbers (single digit ES numbers) but 28.5gr and 29.4gr load showed potential. It's one I'm going to retest for sure...

View attachment 1121161

Oh hell yeah.
At 200 yards 29.4 shot 1/4 Moa at 2872 FPS
Addendum- when I look at 30.0- your still around a half minute testing and your flat out to 30.2
I think you could bring something together30.1 then with seating BAM your rockin
maybe tinker with primers who knows maybe a home run

 

[Lefty Trigger]

Oh hell yeah.
At 200 yards 29.4 shot 1/4 Moa at 2872 FPS
Addendum- when I look at 30.0- your still around a half minute testing and your flat out to 30.2
I think you could bring something together30.1 then with seating BAM your rockin
maybe tinker with primers who knows maybe a home run

30.0 and 30.2 both started showing signs of pressure, primer and snug bolt lift on 30.2

 

[JFrank]

Damn the bad luck

Just messin Buddy you’ll find it

 

[Dusty Stevens]

Some newer varget cant get to 30.0 easily. 30.0 has been my go to load for years. I guess when my current lot from 5-6yrs ago is gone ill have to start over. Always work up to somebody elses suggested load

 

[Mad_Charlie]

Do you think that a chrono could be useful to try to duplicate velocities when you have to use a different lot of a given powder?

I usually find a load recipe that shoots the best, and then chrono, but if I am working with certain combinations, I use the chrono to watch for sudden velocity spikes or drops.

 

[dgeesaman]

After shooting some groups tonight at 300 yds. I'm finding that for the most part the ES numbers really don't help group size,

Play around with changes in velocity on a ballistics program.

You'll find almost no change in vertical in short range. 600-1000y, you'll see the vertical spread out and become significant. So the low ES/SD stuff is for long range.

David

 

[jackson1]

Great read guys many pieces of useful information here. My simple mind will spend many days attempting to digest it all.