Interpreting results of ladder test

R

rotorwag

New member
So I've read various links and posts about ladder testing here on PM and decided to give it a try. Now I'm not sure what the results are telling me. Rifle is Savage M12 14 twist with no mods at all. I used Win brass and primers, Varget from 31.0--36.0 gr by 0.5 gr increment and 55 gr NBT, 2 shots per charge weight. Shot at 280 yds. The day was pretty warm and the mirage was pretty bad, though I let the barrel cool after each pair at each charge weight. Also I have little experience shooting at this distance.

I think I see close vertical separation in the 31.0-32.0 range and also in the 34.0-35.0 range, right? Is this what I'm looking for? Should I now load some more in one of those ranges and play with seating depth? Or something else? The one 31.5 gr round that landed high and left is probably my bad shooting. I don't have access to long range so had to make do the best I could in a farmer's field using a folding table. Actually I thought the horizontal spread was pretty interesting too as I could see my heart beat causing the reticle to slide back and forth across the mark. But if I understood the articles I read correctly, it is the vertical separation that matters anyway.



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That's how I read it too...
2 shots per load, give you the statistical confidence to be able to say.... That you pulled the trigger a few times.
 
Originally Posted By: rotorwagYes. So how many should it have been? Did I waste my time and components?

sorry, but IMO very much so. I usually load up 4 at each charge and if by the third shot its not looking good I don't shoot the 4th, I just like it for the times that I pull a shot I still have 1 more round to do re-shoot. Some people like 5 shots and I do too but components are short so that's why I have switched to doing 4. Then after I get a couple charge weights that are showing nice 3-4 shot groups I duplicate 4-5rds of each and re-test to confirm, from their pick the best one and if needed play with seating depth.

And then I only do load work-up at 100yrds. closer seems to be of no benefit and longer is just that much harder to shoot accurately, consistently.
 
Quote:I think I see close vertical separation in the 31.0-32.0 range and also in the 34.0-35.0 range, right?

That would be my interpretation from information given.

The horizontal dispersion is probably caused by the mirage you mentioned. I may have missed it but didn't see any wind information. Shooting during a boiling mirage will cause a vertical string and a mirage running left to right will cause shot to strike to the right & visa-versa. The faster the ripple the more the mirage is worth. Watch your conditions and try to shoot during same condition shot-shot.

Using the ladder method requires only one shot per charge weight and you look for the area that results in several shots grouping together then select load around middle of that group.

A lot of information can be gleaned from velocity in conjunction w/ladder method if you have access to a chronograph as you will usually see a flat spot in velocities of the shots that tend to form a group.

I would load 3-5 rounds each of 31, 31.5 & 32 gr. and shoot them for grouping, pick the most accurate of the bunch and then play w/seating depth to see if you can improve.

Edit to add link to Creighton Audett's ladder method: http://precisionrifleblog.com/2012/07/13/creighton-audette-ladder-testing/

Regards,
hm


 
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Originally Posted By: midwestpredatorOriginally Posted By: rotorwagYes. So how many should it have been? Did I waste my time and components?

sorry, but IMO very much so. I usually load up 4 at each charge and if by the third shot its not looking good I don't shoot the 4th, I just like it for the times that I pull a shot I still have 1 more round to do re-shoot. Some people like 5 shots and I do too but components are short so that's why I have switched to doing 4. Then after I get a couple charge weights that are showing nice 3-4 shot groups I duplicate 4-5rds of each and re-test to confirm, from their pick the best one and if needed play with seating depth.

And then I only do load work-up at 100yrds. closer seems to be of no benefit and longer is just that much harder to shoot accurately, consistently.

This^

I think factors like wind, mirage, your scopes magnification and just how good of a longer range marksman you are play into ladder testing too much for it to provide consistent repeatable results. What about the rifle? If its a new rifle you dont know spit about it, what it will or wont shoot and how long it will shoot for and the test says you need to shoot it at 300 yards? Again, not consistantly accurate or repeatable IMHO.

 
Originally Posted By: rotorwag
Did I waste my time and components?



Yes. You wasted your time and components.

The problem with these "Fire two rounds and be finished with it" gimmicks like the "Ladder test" and the "OCW" (both are the same), is that they tell you little, if anything, about what the most accurate load is.

What they tell you is, "Shoot a bunch of rounds, pick some on the same horizontal line, and go home."

What they don't tell you is that these magic techniques don't find anything, and you pick a load and stop testing, not knowing that you don't have the best load.

For any method to be accurate, it MUST be repeatable, and the "Ladder" and the "OCW" are not.

Load up another bunch of rounds just the same as the ones you shot and go do it again, at the same distance - if the ladder test is valid, then your new target should look like this one... which it will not.

It makes no difference what range you shoot at, if your shooting skills can make 1" groups at 100, then you can make 4"" at 400 yds (though the rifle may not
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)... however, if you are going to put all your shots on one point of aim, then long distance will make it easier to separate bullet holes if they are not on top of each other.

While vertical is important, horizontal is equally important - what is the point of having a rifle that shoots groups that are 1" high and 7" wide - unless you are shooting alligators and snakes
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This pretty much leaves you that old boring method of shooting groups.
 
I most often load 5 per charge wt. but at a minimum 3.
Looking at what you have there for results though..hehe
I would load up 5 rounds at 35g and see what they do at the same distance. If they are a 1" group at 280 yards then no, you didn`t waste time and components.
I also like 100 yard range for reason posted by midwestpred.
 
Originally Posted By: CatShooterOriginally Posted By: rotorwag
Did I waste my time and components?



Yes. You wasted your time and components.

The problem with these "Fire two rounds and be finished with it" gimmicks like the "Ladder test" and the "OCW" (both are the same), is that they tell you little, if anything, about what the most accurate load is.

What they tell you is, "Shoot a bunch of rounds, pick some on the same horizontal line, and go home."

What they don't tell you is that these magic techniques don't find anything, and you pick a load and stop testing, not knowing that you don't have the best load.

For any method to be accurate, it MUST be repeatable, and the "Ladder" and the "OCW" are not.

Load up another bunch of rounds just the same as the ones you shot and go do it again, at the same distance - if the ladder test is valid, then your new target should look like this one... which it will not.

It makes no difference what range you shoot at, if your shooting skills can make 1" groups at 100, then you can make 4"" at 400 yds (though the rifle may not
wink.gif
)... however, if you are going to put all your shots on one point of aim, then long distance will make it easier to separate bullet holes if they are not on top of each other.

While vertical is important, horizontal is equally important - what is the point of having a rifle that shoots groups that are 1" high and 7" wide - unless you are shooting alligators and snakes
wink.gif
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This pretty much leaves you that old boring method of shooting groups.



I am with you Cat, I have read about the Ladder and OCW way of working up a load and I could never make my pea brain understand how to interpret what the heck they were getting at. My thought is shoot 5 shot groups, work up load in .5 grain jumps. Pick smallest group and tweak that load to improve it. Now I know this is very rudimentary, this is not all inclusive of how I do it. But just the general gist.

Why try and make it more complicated than it is.

And don't give me the old song and dance about saving components. If I have to burn a barrel out finding a load, NO BIG DEAL. I am exaggerating in this statement.

Heck I even work up loads for bullets I have really no intention of using. I do it cause it is fun and I enjoy the heck out of it.



 
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Why not just shoot groups to find the best load? It's not that hard. I've tried the ladder test a couple times and it was a complete waste. BS as far as I'm concerned. Doesn't matter where groups are hitting on paper (scopes adjust), just how tight they are. And the OCW is even more BS......getting through only 1/2 page of that website was my limit. Amazing some of the stuff that gets put over as "the deal" and people buy into it.
 
Quote:What they don't tell you is that these magic techniques don't find anything, and you pick a load and stop testing, not knowing that you don't have the best load.

For any method to be accurate, it MUST be repeatable, and the "Ladder" and the "OCW" are not.

One advantage of the ladder method is that it can reveal the best component to choose for your rifle quickly. Note the two different "accuracy nodes" (AN) with varget and none obvious with 4895 shown on graphs below. This allowed shooter to eliminate 4895 in short order for his particular rifle which obviously preferred Varget.

The ladder method is much more effective when used in conjunction w/a chronograph. Benefit of chronograph is obvious when you note the small extreme velocity spread (ES) of velocities within the two chosen ANs.

Selecting the middle charge within either AN eliminates the need for weighing powder charges as there is only 4 fps difference in MV with .4 gr. variation in powder charge on the first and 22 fps on the higher velocity node. The longer the range, the more important ES becomes.

Another benefit of ladder test is it allows one to identify the upper pressure limits without necessity to break down the other four rounds once that point is reached w/conventional group shooting. Once all of the above have been determined, then comes the group shooting to fine tune the load.

As for repeatability of a ladder test, if a shooter can shoot repeatable groups with a given rifle, he can repeat the ladder test as both are dependant upon the same factors, including, but not limited to:

1)Shooter ability
2)Rifle ability
3)Weather

OP mentioned that he was shooting from a folding table, (not the most stable platform for precision shooting) and that mirage was quite noticeable. Either of these conditions can have a large effect on results.



To each his own, but I find the ladder method to be very enlightening and an effective tool in load development, especially for long range shooting.

Regards,
hm
 
The only problem is... if you repeat the exact same test 5 times, the results will be different for each test.

They had a big "ladder" shoot-out at my club two years, with repeat loads tested, and at the end of it - none of the targets made any sense.

It always looks good when one set is presented... but when the same set of loads are shot on five targets, and all of it presented, it looks like scat.
 
Ok then, load up 25 rnds at 35g and shoot 5 each at 5 different targets, if they all group around a inch at 280 yards then your work is done. or if the range is close do 5 at a time
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Thanks, everyone, for the feed back. With so many options in components and so little time to load/shoot, I had hoped to find a good load quickly. I'll keep playing with it though.
 
Originally Posted By: CatShooterThe only problem is... if you repeat the exact same test 5 times, the results will be different for each test.

They had a big "ladder" shoot-out at my club two years, with repeat loads tested, and at the end of it - none of the targets made any sense.

It always looks good when one set is presented... but when the same set of loads are shot on five targets, and all of it presented, it looks like scat.

Tell me more of the details on the "ladder shootout". Type/quality of rifles used, conditions, ability of shooters, did conditions remain constant (If so, where are you located, our range is not that blessed.) etc.? If your club is like mine, all of the above will run the gamut from best to not so good. Some of our shooters are High Masters all the way to unclassified, shooting custom target rifles to grandpa's deer rifle. Under these parameters, I would expect a confusing outcome trying to decipher five consecutive ladder tests.

As for duplicating a ladder test, or for that matter a five shot group, five consecutive times, the odds are really against any shooter. Have you ever shot five identical 5 shot groups? I know I can't remember ever doing so.
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I don't shoot my best every time I go to the range and I know of few who do. What I'm getting at is there are lots of variables to consider and few absolutes as you well know. The author of the article I linked above says it better than I have been able to do:

Quote:A drawback of the Audette Method is that EVERY shot is figured into the “ladder”. If your rifle is prone to vertical dispersion (due to poor bedding, stock flexibility, poor quality optics, etc.) you may never be able to find the sweet spot based on any process that evaluates individual shots. Simply stated, the normal dispersion of rifles that are less than benchrest quality will give false indications and overshadow any meaningful results. With benchrest quality rifles (Creighton Audette’s first love), the Ladder Method works extremely well. But it can be error prone for sporters and other less precise rifles. The use of a chronograph can help, but ultimately the ability to see how the bullets group on the target is also critically important.


I'm not sure you can use a group shoot with so many individuals shooting various firearms to discredit the value of the ladder method.

I am still of the opinion that an experienced shooter (who can reliably call a bad shot should it occur within a string), using good equipment and with reasonably decent shooting conditions can reliably find the accuracy nodes within which he/she can expect to develop the best load for his rifle.

Regards,
hm
 
I feel I shoot pretty well but I wouldn't trust myself to get any info from 300 yards when trying to get a good accurate load you would need to be rock solid steady,no wind, just a perfect setup. That probley will not happen. Test at 100 yards till you get some tiny little clover leaf groups, then take those loads out to 300 yards and see how it does...Jason
 
Originally Posted By: hm1996

As for duplicating a ladder test, or for that matter a five shot group, five consecutive times, the odds are really against any shooter. Have you ever shot five identical 5 shot groups? I know I can't remember ever doing so.
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Now, that is the crux of the problem... if you can't trust that you are shooting the test the same way, how can you trust the outcome.

If you load up 5 batches of loads - each bunch is 35, 35.5, 36. 36.5 37, 37.5

Then you shoot the first string on paper.

Then you shoot the second string on paper, etc.

IF, there is any meaning to the ladder test, you should be able to give a target to each of five people, and they should each come up with the same recommendation for the best load.

But they cannot, because each target will give a different "best load indication".

If that is true (and it is) then if you shoot the five, which one do you trust.

If you only shoot one, then you don't know which variation you have - in effect, if you shoot a ladder of the same load string, each day for a month, each day you would get a different "best load"..., which means you have nothing at all.
 
Quote:If you load up 5 batches of loads - each bunch is 35, 35.5, 36. 36.5 37, 37.5

Then you shoot the first string on paper.

Then you shoot the second string on paper, etc.


I guess this is the method used in your club's "ladder shoot"?

Quote:But they cannot, because each target will give a different "best load indication".

If that is true (and it is) then if you shoot the five, which one do you trust.

Guess I'm just lucky, but have never found it necessary to shoot more than one ladder test and have managed to stumble on to some pretty fair loads so far.
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My pet 600 yd. load was developed from a single ladder test:


This 20 shot string measured 1.1" was developed from single ladder string:



As was this short range load:



Hey, I'm not saying the old "shoot groups of 3-5 shots" w/various loads will not come up with good loads. I used that method for 25 years or more before learning of Audett's shortcut and have used it ever since. It's just one more tool in the box and is quickest method I've found to find a load that can be thrown, not weighed (AN) and result in groups as shown above.

Guess the old saying that even a blind hog manages to find an acorn once in a while is true so I'll just keep on dancin' with the gal that brung me until she steps on my toe.
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Regards,
hm
 
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