Ladder load results help

[7mm-08 Freak]

OK guys wheres my node? Obviously its not 40.3 or 42.1 they were the worst. That is 2 strings, Same day, shot in opposite order (Low to high then high to low). Carefully look at the different colors on the graph. They are almost identical. the load is a 243 Winchester, 85 gr TSX, RL-16 powder, Lapua brass, 210M primer. Did I do something wrong?

 

[kthomas]

Your test has a sample size that's statistically irrelevant to determine any velocity "nodes".

The only thing you can determine from your test is approximate velocity per powder charge and where pressure is (which will be determined by physical signs on the brass and bolt lift).

 

[7mm-08 Freak]

Your test has a sample size that's statistically irrelevant to determine any velocity "nodes".

The only thing you can determine from your test is approximate velocity per powder charge and where pressure is (which will be determined by physical signs on the brass and bolt lift).

Ya lost me. I have done this same test and seen wildly different results in other guns. What do I do differently? None were heavy bolt lift or high pressure signs that I could see. That is 1 grain above book min to book max range of powder

 

[kthomas]

Ya lost me. I have done this same test and seen wildly different results in other guns. What do I do differently? None were heavy bolt lift or high pressure signs that I could see. That is 1 grain above book min to book max range of powder

I used to do what you do, thinking I would find "nodes" through the Satterlee method.

Then I started loading up multiple identical ladders, and found that with more data (aka larger sample sizes), any so called "nodes" that I found using a ladder weren't "nodes" after all.

Use that ladder to get an idea of what velocities you get per powder charge, and where pressure begins (if you saw any pressure). There's not enough data to conclude if there's a velocity node or not.

 

[7mm-08 Freak]

I used to do what you do, thinking I would find "nodes" through the Satterlee method.

Then I started loading up multiple identical ladders, and found that with more data (aka larger sample sizes), any so called "nodes" that I found using a ladder weren't "nodes" after all.

Use that ladder to get an idea of what velocities you get per powder charge, and where pressure begins (if you saw any pressure). There's not enough data to conclude if there's a velocity node or not.

I just want to know what the OCW is and what is max. After that I like to find what jump is best. Those Barnes monolithic bullets DO NOT like being jammed into the or right off the lands. Somewhere in the .050-.075 off is the best I have found.

 

[kthomas]

Okay.

You need test targets to determine OCW nodes.

Your testing will not find any velocity nodes.

There's nothing here for the 'hide to interpret or analyze.

 

[7mm-08 Freak]

Okay.

You need test targets to determine OCW nodes.

Your testing will not find any velocity nodes.

There's nothing here for the 'hide to interpret or analyz

Well, hear me out on this. I’m not being an ass and I’m not trying to be a jerk that you’re telling me that all these people that are shooting across lab radars and shooting across magneto’s are wasting their time? I’ve been told there are two ways to do. This. One of them is to shoot paper at 300 or further and the other is check for speed with an accurate device. You’re saying that paper is the only way to do this correctly? If you’re telling me paper is the only way to do it correctly you’re introducing a lot of variables into the equation when shooting a hunting rifle. I’d be interested in you posting a link to educate those of us that are obviously doing it wrong and once again, I’m not being a smart ass I’m trying to learn.

 

[BuildingConceptsllc]

Do a pressure ladder first to see what range you have to work with. When you hit pressure, that's the high charge weight. Drop down 3 grains below that and that's your low charge weight starting point.

With that range of charge weight

Load up a ladder in .25 gr increments. Then number the groups and shoots the numbers at random or some other way to be "blind". Then see where your POI (point of impact) moves. There will be an area in there where you will see the 3 rounds start moving to and over 3 or more charge weights you will see that they have same point of impact as a group.

Then pick the middle of that charge weight.

Then do a seating depth ladder with only your selected charge weight. This should be a long ladder. Start like 10thou off the lands and then go to 100 thou off with 3 shot groups. Make your jumps in 5 thou increments. Pick the one that had a tight group on either side of it and that's your seating depth.

You're done. (The various jumps in charge weight and seating depth is up to you, some done want to shoot that much but this way will work every single time, all the time and get a good load. You don't just "have to" go 3 grains below first pressure but it's the best overall way I've found and often there are a "high" and "low" that do the same basically it just depends on how fast you want to run and brass life you want.)

 

[BuildingConceptsllc]

Well, hear me out on this. I’m not being an ass and I’m not trying to be a jerk that you’re telling me that all these people that are shooting across lab radars and shooting across magneto’s are wasting their time? I’ve been told there are two ways to do. This. One of them is to shoot paper at 300 or further and the other is check for speed with an accurate device. You’re saying that paper is the only way to do this correctly? If you’re telling me paper is the only way to do it correctly you’re introducing a lot of variables into the equation when shooting a hunting rifle. I’d be interested in you posting a link to educate those of us that are obviously doing it wrong and once again, I’m not being a smart ass I’m trying to learn.

You are talking about something different than he is.

 

[kthomas]

Well, hear me out on this. I’m not being an ass and I’m not trying to be a jerk that you’re telling me that all these people that are shooting across lab radars and shooting across magneto’s are wasting their time? I’ve been told there are two ways to do. This. One of them is to shoot paper at 300 or further and the other is check for speed with an accurate device. You’re saying that paper is the only way to do this correctly? If you’re telling me paper is the only way to do it correctly you’re introducing a lot of variables into the equation when shooting a hunting rifle. I’d be interested in you posting a link to educate those of us that are obviously doing it wrong and once again, I’m not being a smart ass I’m trying to learn.

Loading up 2 rounds of each powder charge is simply not enough info to find any velocity "node".

Don't take my word for it, try it for yourself.

Load up 5 rounds of each powder charge and compare it to your previous ladder. Or better yet 10 rounds. Or 20. See which charge weights produce a velocity "node". Continue to shoot those different charge weights on different days with different environmental conditions. Is that "node" still a node? Are any previously identified powder charge "nodes" still the tightest node?

My process is simple. I do a velocity ladder to understand what approximate velocity I get per powder charge, and where pressure is. From there, I identify which velocity I want to hit, and I load up ammo to that velocity. I use Berger Hybrids, I know that I can seat them 10 thou off the lands and they will shoot. I don't change OAL through the life of the barrel by chasing the lands.

Reloading is easy if you use good quality gear, good quality components (Lapua brass, Berger bullets), and have a simple and consistent process.

 

[straightshooter1]

Well, hear me out on this. I’m not being an ass and I’m not trying to be a jerk that you’re telling me that all these people that are shooting across lab radars and shooting across magneto’s are wasting their time? I’ve been told there are two ways to do. This. One of them is to shoot paper at 300 or further and the other is check for speed with an accurate device. You’re saying that paper is the only way to do this correctly? If you’re telling me paper is the only way to do it correctly you’re introducing a lot of variables into the equation when shooting a hunting rifle. I’d be interested in you posting a link to educate those of us that are obviously doing it wrong and once again, I’m not being a smart ass I’m trying to learn.

Yes, all those people are wasting their time, though one might, out of pure luck" select a charge that is in a good accuracy node. Have you notice "all these people" only run the test once? If the run the test one or two more times, they'll find very different results. And the fact that the results can't be duplicated is evidence enough that such a velocity OCW type of test just doesn't really work. The OCW test was designed to work on target results, not velocity.

You're right about the problem for shooting paper at 300 where environmentals can really mess things up. This is why it's recommended that it's done with the environmentals are at their best for 300 yds. or anything longer than 100 yds. If done at 100 yds., environmentals will have very little effect on paper making it easier to interpret what's going on with the loads. When doing the OCW test, one needs to learn how to read what's happening on paper.

 

[7mm-08 Freak]

Yes, all those people are wasting their time, though one might, out of pure luck" select a charge that is in a good accuracy node. Have you notice "all these people" only run the test once? If the run the test one or two more times, they'll find very different results. And the fact that the results can't be duplicated is evidence enough that such a velocity OCW type of test just doesn't really work. The OCW test was designed to work on target results, not velocity.

You're right about the problem for shooting paper at 300 where environmentals can really mess things up. This is why it's recommended that it's done with the environmentals are at their best for 300 yds. or anything longer than 100 yds. If done at 100 yds., environmentals will have very little effect on paper making it easier to interpret what's going on with the loads. When doing the OCW test, one needs to learn how to read what's happening on paper.

I purposely ran it 3 times for that very reason those results are the 2nd and 3 time. Previous numbers look identical. I'm so confused now my head hurts. its obvious the starting and ending loads are not good (73 & 29 fps difference) the rest are within 3-4 fps. There is the actual scratch paper from the range.

 

[kthomas]

I purposely ran it 3 times for that very reason those results are the 2nd and 3 time. Previous numbers look identical. I'm so confused now my head hurts. its obvious the starting and ending loads are not good (73 & 29 fps difference) the rest are within 3-4 fps. There is the actual scratch paper from the range.

Then load up whatever you think your "nodes" are and compare them with other charge weights.

Do a constant comparison over a chrono over different days and conditions.

If it truly is a node, then great. If not, it should still shoot well as long as you have a good process, equipment and components.

Either way, it's a win/win.

 

[straightshooter1]

I purposely ran it 3 times for that very reason those results are the 2nd and 3 time. Previous numbers look identical. I'm so confused now my head hurts. its obvious the starting and ending loads are not good (73 & 29 fps difference) the rest are within 3-4 fps. There is the actual scratch paper from the range.

Because there are so many variables at play, some that are just not controllable, I've never seen how one can get enough consistency in velocity for this kind of ladder tests to work . . . especially if one isn't capable of getting really low SD's.

Bryan Litz newest Applied Ballistics book confirmed all that I suspected. Here are a couple pages from his chapter on Ladder Testing that he performed that might be of some help to you:

 

[MarkyMark007]

OK guys wheres my node?

 

[MarkyMark007]

Your test has a sample size that's statistically irrelevant to determine any velocity "nodes".

the most funny thing of the year!

 

[rijndael]

Because there are so many variables at play, some that are just not controllable, I've never seen how one can get enough consistency in velocity for this kind of ladder tests to work . . . especially if one isn't capable of getting really low SD's.

Bryan Litz newest Applied Ballistics book confirmed all that I suspected. Here are a couple pages from his chapter on Ladder Testing that he performed that might be of some help to you:

View attachment 8019307 View attachment 8019308

View attachment 8019331

Can you clarify which book?

Modern Advancements in Long Range Shooting Vol. III ?

 

[straightshooter1]

Can you clarify which book?

Modern Advancements in Long Range Shooting Vol. III ?

Yes

 

[straightshooter1]

For those who are unfamiliar with barrel harmonics . . .

In trying to KISS this, every barrel has it's own harmonic vibration that is a sine wave that's along the length of the barrel:

When we talk about finding the "node", we're actually trying to find the area at the "antinode" of the wave where the motion is at it slowest at the muzzle for most consistent release of the bullet. So, the timing of the bullet to get to the muzzle release at the pint of the harmonic antinode is the goal for finding "the node".

Because long and/or heavy barrels have a lower frequency than short and/or lighter barrels, the time around antinode is longest, which is why it's easier to find and stay in "the node" with the longer and/or heavier barrels.

I choose the red.

 

[RegionRat]

@7mm-08 Freak did you save the targets you shot at during your work-up or did you just shoot for the chronograph data?

What the folks are telling you is true, that is, that testing a spread of charge steps for velocity data alone is not how you find an OCW or a "node", or wring the best accuracy or precision out of a rig.

If we assume the goal is to find a load that gives the best accuracy or precision and maximizes the gun and recipe potential, then you will have to work with target data.

Another way to look at this problem is in reverse... if the velocity stats really suck, could the group at distance be good?

Once the distance gets to be far enough down the trajectory to show vertical spread due to velocity differences, most centerfire rounds will have to do "good enough" with velocity stats or the vertical component will have a spread proportional to at least the speed stats plus more due to the other harmonics. In other words, for a group to be "good" at distance, by definition the speed stats are "good enough".

At shorter distances, the trajectory will not show the vertical spread of the speed stats. It is possible to have pretty poor speed stats and still get good groups at short ranges.

Lots of words to say... prioritize the targets and then look at the speeds.

It isn't that we are telling you the velocity or ES/SD doesn't matter at all, but we are telling you that your load development method should first prioritize the groups and then the speed stats. Most times, if you get a good honest group at the distance you care about, the velocity stats will be "good enough" by definition.

If the speed stats were so bad that they could hurt the group, you wouldn't call it a good group. The opposite isn't true, i.e., if you have great ES/SD in a carry gun, you don't necessarily see a good group if those come at the wrong speed for all those other harmonics.

With carry rigs, stocks are usually not stiff and barrels are of a light profile. Compared to competition rigs that have heavy bbl sections and stiff stocks, carry guns are a challenge due to structural harmonics in addition the the internal ballistics that are responsible for velocity stats.

Try re-reading the OCW Method or the Audette Ladder method and if you don't follow what those tests are doing, then circle back.
The graphics in the Audette article are terrible and the article deserves a clean-up with good charts, but here it is.
chrome-extension://efaidnbmnnnibpcajpcglclefindmkaj/https://precisionrifle.wpenginepowered.com/wp-content/uploads/2012/07/incremental-load-development-method.pdf

chrome-extension://efaidnbmnnnibpcajpcglclefindmkaj/https://precisionrifle.wpenginepowered.com/wp-content/uploads/2012/07/excerpt-on-creighton-audettes-20-round-string-load-development.pdf

The links for Dan Newberry's articles don't seem to work any more, but the OCW and OBT topics have been covered in many strings.
http://www.the-long-family.com/optimal barrel time.htm

An OCW test is supposed to increment powder charge, shoot groups, take the centroid of the groups and select the "node" by using the widest charge range where the group centroids change the least for at least several charge steps. That means you must ignore the group size at first, then circle back and work the group down with seating depth, then examine the speed stats.

The Audette method uses distance as a leverage to expose the harmonics, the OCW method can be shot at shorter distances. You will want target analysis software to help find the group centers the easy way when doing an OCW style test. YMMV

Good Luck.

 

[7mm-08 Freak]

I did not keep the targets. I shot for speed. The targets were at 100 yds and all were in a 1/2" group most of them touching. Obvious way to close per everything ive seen heard or read, 300yds is the minimum everybody says. ill never hunt with this rig past 300. I have to say I am not a big fan of "long range"with a 243Win on deer size game. I like 1000lbs or energy and at 350 this load is just under that. I think ill just load up some at 41.3 and call it good at this point. 1/2" at 100, and 1" at 200 is fine for small deer and varmints. This is NOT a long range hunting rig like my 280AI. I appreciate all the comments and not dragging me. Ive been reloading for 35 years but have really gotten good in the last 5 or so. ALL my hunting guns are medium end over the counter stuff. I cant spend 5-6K on a bench gun. Im gonna confess. I have had 6 Christensen Ridge lines with CF barrels. Laugh if you want all of them were 2-3"+ guns out of the box. I put some Bix N Andy triggers in em, reworked the crappy bedding and they all shoot .5MOA or better out to 300 with my reloads now. Thank you guys for all the help.

 

[MarkyMark007]

For those who are unfamiliar with barrel harmonics . . .

In trying to KISS this, every barrel has it's own harmonic vibration that is a sine wave that's along the length of the barrel:
View attachment 8019627
When we talk about finding the "node", we're actually trying to find the area at the "antinode" of the wave where the motion is at it slowest at the muzzle for most consistent release of the bullet. So, the timing of the bullet to get to the muzzle release at the pint of the harmonic antinode is the goal for finding "the node".
View attachment 8019629

Because long and/or heavy barrels have a lower frequency than short and/or lighter barrels, the time around antinode is longest, which is why it's easier to find and stay in "the node" with the longer and/or heavier barrels.

I choose the red.

you are on blue pill because you are constantly lying about nodes, which does NOT exists.