Vertical Dispersion: Flat spots on the MV ladder test are meaningless

[paulT]

Here is an old load development for my Steyr SSG04 300WM rifle (hunting/intro sharpshooting rifle).
You can compare load 2, 3, 4. Note, that load 2 had smaller dispersion but high MV SD. Load 4 has very small MV SD, but the dispersion grew.

I had better examples, but I have to look for them.

300 WM 225gr ELD-M H1000 load development.xlsx

1drv.ms

Took a look at your test data which shows lowest sd & es with your 46g load question did you also try tuning the 46g load by a seating depth load testing of the 46g load?

 

[tom]

If @Beiruty is saying bullets converging doesn't line up with lowest es, then I would say I wouldn't disagree at all. I've only performed powder ladders, as in bullets going through paper, as far as 2,075 yards, so my observations are limited to that and shorter. Once in a while a great grouping load will register a low es, but often not average the lowest es. Have to admit I skipped through most of the thread once it became a dog pile.

Tom

 

[davidjoe]

If @Beiruty is saying bullets converging doesn't line up with lowest es, then I would say I wouldn't disagree at all.

A number of people say this, but a 0 ES is the only logical goal. There is a real problem with accepting non-correlation as being true. For consecutive bullets shot at different velocities, if they went through the same hole, it was due to luck, meaning a flinch, bad aiming, the wind, a bullet defect, etc.

In a tunnel with a constant hold, It is simply not possible for identical bullets to hit exactly the same place if they have different velocities. They will necessarily drop, spin, and spin drift at different rates. That we don’t shoot in a tunnel, does not mean that now a certain amount of ES that is bigger than 0, becomes good for accuracy.

 

[Beiruty]

Took a look at your test data which shows lowest sd & es with your 46g load question did you also try tuning the 46g load by a seating depth load testing of the 46g load?

Load 5,6,7 are verification for load 4. Note: OCW node, meaning the impact of the bullets relative to the point of aim are still holding. SD/ED jumped a lot, and it could be caused by hunting-quality brass that I was using. No Lupua 300WM brass at that time.

When pushed out the COAL for the 2 loads last loads, 8, 9 the dispersion grew.

 

[Tarmacshooter]

I’m pretty sure you should keep digging at your reloading bench. Your consistency would improve significantly. I’m also using an inherently more accurate round.

 

[Dave Way]

If @Beiruty is saying bullets converging doesn't line up with lowest es, then I would say I wouldn't disagree at all. I've only performed powder ladders, as in bullets going through paper, as far as 2,075 yards, so my observations are limited to that and shorter. Once in a while a great grouping load will register a low es, but often not average the lowest es. Have to admit I skipped through most of the thread once it became a dog pile.

Tom

Don’t they give awards for the lowest ES’s at the matches you shoot Tom?

 

[Tom E]

That was a waste of 30 minutes I’ll never get back,
I did learn a few things I guess, no one tunes a gun at a 1000
None of us know what a ladder is , wether it has 1 shot or 2 maybe even 3.
And Dave I just spit Dr Pepper on my shirt on the lowest es match

Maintain

 

[Tarmacshooter]

That was a waste of 30 minutes I’ll never get back,
I did learn a few things I guess, no one tunes a gun at a 1000
None of us know what a ladder is , wether it has 1 shot or 2 maybe even 3.
And Dave I just spit Dr Pepper on my shirt on the lowest es match

Maintain

This is why I try and stay out of these sub forums. Most of the time it’s completely inaccurate information.

As far as not tuning at 1000. I’m sure some do. But wind, sun and mirage make it difficult. Also some may not have the luxury of having access to 1000 yards on a regular basis.

We tune at 500. That’s what we have.

 

[Tom E]

This is why I try and stay out of these sub forums. Most of the time it’s completely inaccurate information.

As far as not tuning at 1000. I’m sure some do. But wind, sun and mirage make it difficult. Also some may not have the luxury of having access to 1000 yards on a regular basis.

We tune at 500. That’s what we have.

I only get on the comp thread and 6br occasionally plus classifieds as well
Think I’ll stick to that

Done a lot of tuning at 500 as well out of the shop, but I’m am lucky that we have a 1000 yd range over the hill from the house

 

[tom]

Don’t they give awards for the lowest ES’s at the matches you shoot Tom?

It's lowest IQ Dave. It's a close race, still to be determined.

Tom

 

[Tarmacshooter]

I only get on the comp thread and 6br occasionally plus classifieds as well
Think I’ll stick to that

Done a lot of tuning at 500 as well out of the shop, but I’m am lucky that we have a 1000 yd range over the hill from the house

Sage advice.

 

[INTJ]

This thread illustrates a classic problem. There are certain personality types--often newer shooters--that try to theorize and calculate their way to small groups at long range. There are others that reject almost all theory and only count actual experience. These two personality types usually do little more than argue with each other.

I think a better way is to develop theories, collect data, and do the math; but then go shoot and realize the true test is what we see on paper. A theory that doesn't work has little validity. With that in mind.......

Its very hard to shoot enough shots to have a meaningful statistical analysis. The barrel changes with every shot fired. Conditions change with every shot fired. Each piece of brass is different, as is each bullet, primer, and kernel of powder. Not to mention the difference in how we pull the trigger each time, how the rifle recoils, etc.

So we don't have any real constants for our analysis. Unless we just decide that all rifles are 2 MOA rifles, we need a different way.

We load as consistently as we can, shoot our target as consistently as we can, track conditions, groups, other data, etc. Then we constantly refine. From that, we can make GENERALIZATIONS. We can find things that are consistent most of the time, but understand nothing is 100% when it comes to shooting.

This process describes 1000 yd BR shooting. We shoot smaller groups at 1000 yds more often than anyone else. We constantly re-tune our loads. We know a lot more about what usually works than why it works.

All that is very frustrating to those who are used to arriving at the correct answer based on pure data analysis.

 

[Tarmacshooter]

This thread illustrates a classic problem. There are certain personality types--often newer shooters--that try to theorize and calculate their way to small groups at long range. There are others that reject almost all theory and only count actual experience. These two personality types usually do little more than argue with each other.

I think a better way is to develop theories, collect data, and do the math; but then go shoot and realize the true test is what we see on paper. A theory that doesn't work has little validity. With that in mind.......

Its very hard to shoot enough shots to have a meaningful statistical analysis. The barrel changes with every shot fired. Conditions change with every shot fired. Each piece of brass is different, as is each bullet, primer, and kernel of powder. Not to mention the difference in how we pull the trigger each time, how the rifle recoils, etc.

So we don't have any real constants for our analysis. Unless we just decide that all rifles are 2 MOA rifles, we need a different way.

We load as consistently as we can, shoot our target as consistently as we can, track conditions, groups, other data, etc. Then we constantly refine. From that, we can make GENERALIZATIONS. We can find things that are consistent most of the time, but understand nothing is 100% when it comes to shooting.

This process describes 1000 yd BR shooting. We shoot smaller groups at 1000 yds more often than anyone else. We constantly re-tune our loads. We know a lot more about what usually works than why it works.

All that is very frustrating to those who are used to arriving at the correct answer based on pure data analysis.

I’m pretty sure I’ve been saying this for a few days. Maybe it’s my delivery?

 

[LRPV]

I see a difference in the end user purpose of these load development methods to create confusion. Load development for benchrest is meant to create the smallest groups at a given distance. It doesn’t matter what the MV ES is at the muzzle when the bullets converge at the intended distance. I have proven to myself that a good 1k load won’t shoot the best at 600 or 330yds. Same goes the other way around. A tuner is an excellent tool for shooting groups at a given distance or to keep in “perfect” tune throughout the day. I watched 25ES loads print groups in the 1-2 inch range at 930 yards this week. You mathematicians will say that’s impossible but you’re wrong.

Load development for a PRS type game where multiple distances are engaged are going to see more success with a low ES load. It may not necessarily shoot the best at a certain given distance (pick one) but it will give the competitor a better chance of making impacts at the various distances because your ballistics will vary less. It’s a different game.

Benchrest shooters and their equipment are at the top of the accuracy food chain whether any of you like it or not. They have paved the way for other disciplines from the beginning. Sure there are many ways to arrive at a location but who do you think surveyed the ground, charted the hills and valleys and then wrote the maps?

Good thread for the most part. It’s been boring around here. See some of you next week.

 

[Tarmacshooter]

I see a difference in the end user purpose of these load development methods to create confusion. Load development for benchrest is meant to create the smallest groups at a given distance. It doesn’t matter what the MV ES is at the muzzle when the bullets converge at the intended distance. I have proven to myself that a good 1k load won’t shoot the best at 600 or 330yds. Same goes the other way around. A tuner is an excellent tool for shooting groups a a given distance or to keep in “perfect” tune throughout the day. I watched 25ES loads print groups in the 1-2 inch range at 930 yards this week. You mathematicians will say that’s impossible but you’re wrong.

Load development for a PRS type game where multiple distances are engaged are going to see more success with a low ES load. It may not necessarily shoot the best at a certain given distance (pick one) but it will give the competitor a better chance of making impacts at the various distances because your ballistics will vary less. It’s a different game.

Benchrest shooters and their equipment are at the top of the accuracy food chain whether any of you like it or not. They have paved the way for other disciplines from the beginning. Sure there are many ways to arrive at a location but who do you think surveyed the ground, charted the hills and valleys and then wrote the maps?

Good thread for the most part. It’s been boring around here. See some of you next week.

I’ll add to this as others have stated already, expectations of accuracy differs from discipline to discipline. PRS needs to hit 1 to 2 moa targets at distance. F-Class needs to be under 1/2 MOA though a 20 shot or more string.

 

[BlackGrouper]

In my mind ladder flat spot is when a bullets radius of gyration, combustion efficiency and barrel harmonics all come together.

When I find that precise harmony I put on a sling, lay down and shoot 9's while second guessing my wind calls.

 

[JFrank]

I’ll add to this as others have stated already, expectations of accuracy differs from discipline to discipline. PRS needs to hit 1 to 2 moa targets at distance. F-Class needs to be under 1/2 MOA though a 20 shot or more string.

Why add anything? Jason “the iceman” Walker 2021 - 600 and 1000 yard IBS Champion said it quite well.

 

[davidjoe]

This process describes 1000 yd BR shooting. We shoot smaller groups at 1000 yds more often than anyone else. We constantly re-tune our loads. We know a lot more about what usually works than why it works.

This is is the kind of candor that sets up advancement of the ball. It is very hard to distill explanations with a thick tube of steel and velocity in the way of visual observations.

We do know that bullets follow natural laws as they are just faster thrown rocks, at the end of the day. (I’m not being glib, generalizing just from a couple different 700’s in the closet, I’m mainly Fclass but I build up and shoot match guns from .22 to BMG, for myself, with backyard shooting ability exceeding ELR match distance.)

While we don’t know all the whys, tuning explanations that don’t follow the reality of physics, cannot be the reason behind the veil. If I were to cut the end of the nose off a bullet, and I have done this, it would be lighter, and leave the muzzle faster. It would have a lower BC, and yes, that means it would converge at some distance with a perfect bullet. (When I did this, and more, I really restrained myself from saying a thing or two about 100 yard BR).

But identical bullets, shot at different velocities, diverge immediately, and continuously, from the barrel onward. I’m not saying it’s a lot, just that it’s true. It would be hard for guys here to agree on much, if they don’t agree with this precept.

 

[LRPV]

Why add anything? Jason “the iceman” Walker 2021 - 600 and 1000 yard IBS Champion said it quite well.

Let’s not get too carried away here. Blind squirrel finds a nut every now and then.

 

[Dave Way]

Let’s not get too carried away here. Blind squirrel finds a nut every now and then.

And some squirrels find lots of nuts! See you in Georgia you blind squirrel.

Dave.