ladder test? does it work

[Eaglet]

GG,

I'm shocked!

[ QUOTE ]
In my humble opinion, ladders were invented for guys who either didn't want to buy chronographs or didn't know how to read what they were telling them. A few guys have since added the chrono to the equation, but then if you're doing that, you might as well just use the chrono and throw out the ladder.

[/ QUOTE ]

Ladder tests simply do make a lot of sence and do work specially if you can use chronographs. The idea in it's self is so simple that complicated minds like CS just can't see it. Same when Christ came, all those highly educated theologians were so elevated on their own education that they rejected Him.

I fully agree with AJ Peacock! Finding, graphing the data for the verticals, comparing the info with the muzzle velocities etc, it's just awesome info. It almost talks back to you!

JMO. /ubbthreads/images/graemlins/smile.gif

 

[goodgrouper]

Yeah, we're barely awake out here in the desert. Been a busy week.

I don't use the ladder test so I don't have conflicting data.

What do you do when your preferred ladder load has a high standard deviation? Work up another ladder? All my ammo and the ammo I load for my clients is loaded like each shot is going to kill a deer at over 1000 yards so if it doesn't have a low velo spread it ain't gonna get fired at an animal. Ladders don't pay attention to velocity spreads until you run them through a chrono and then it is after the fact so to speak. Probably be ok if you're shooting mid-range targets though.

As to your mule deer question, no, Utah Division of Wildlife circuses-errrr services have pretty much eradicated Utah's once famous deer herds. There are only but a few good ones left but they are on draw tags that are next to impossible to get. Used to be a guy could have a chance at a nice buck on the general season hunt but now you have to live with the deer to do that anymore.

 

[goodgrouper]

Hope I didn't shock you too much my friend!

I never said they didn't have merit. I think they show you some valuable information. I simply see the holes in the information they give you. By all means, if you like them, keep using them. I was just trying to show the imperfections with them that no one as yet has been able to answer for. But what do I know, I only make a living making guns shoot across 10 or more football fields accurately and I have never once needed to run a ladder to get the performance my clients need. The chronograph buildup method looking for nodes and pressures with small repeatable velocity deviations just seems to give me more concrete and dependable long range accuracy.

 

[grit]

Hi GG,
When I first started shooting long range (2 years I believe) I put together the equiptment I thought necessary. The next step was to develop a load. I came on here and ran searches on "load development". Then I asked several questions. Seemed the two reponses I got were ladder test and OCW. I chose to try the ladder.
I have had good success finding loads that shoot well at 100 yards. I also run a test group or two at 500. Typically that's been the extent of my load development. I would then shoot these loads over a chrono for the sake of having mv's for drop charts.
Initially I was excited to score a hit at 1k. Now, I occassionally experience a shot missing high or low I think should have scored. I am very happy with the progress I have made. I think it may be time to further refine my loads. Start checking for es/sd.
It sounds like there are two factors contributing to an accurate long range load. One being a node generally believed to be based on barrel harmonics. The other factor being a low es/sd node. Based on ??? Load density, concentricity, uniformity of brass, seating depth....???
Further, it sounds like you belive the ladder method has the ability to point out harmonic nodes but not es/sd nodes??

It's late, I'm tired. I fear I'm rambling. So, I'll get to the point. I respect your opinion and would be grateful if you would share some of your load development method.

Necessary equiptment: chrono Mine is a Chrony, Alpha. 95.5% accurate according to specs. Is this accurate enough (15fps at 3000fps)? If not, which one?
wind flags?

Important factors: brass prep, seating depth, load density, burn rate/barrel length ??

You look for sd nodes coinciding with good groups?

I'm sure I'll come up with more after a few hours sleep. Thanks.

 

[AJ Peacock]

[ QUOTE ]
[ QUOTE ]
A chronograph is a intrinsic part of a proper ladder test .



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So what do you do when the chrono tells you something different than the ladder? And what do you do when the ladder load has a high standard deviation? Which one do you put more stock in?

[/ QUOTE ]

GG, all my ladders are shot over a chrono. I also look for loads with low velocity spreads. When I graph the sum of the velocity spreads over every 3 shots and vertical spreads, I normally see the same node in both charts (the data sets tends to support one another). On the other hand, I have seen nodes in the velocity graph that wouldn't group worth beans (don't ask me why, its not ALL about velocity).

One of my velocity goals in LR load development is to have 2 standard deviations of the velocity, fall within a range that causes less than 1/4 MOA vertical change at 1000yds.

According to Exbal, for the 338AM at 1000yds, that means a standard deviation around 6fps, so 2 standard deviations from the mean would be 12fps. That would mean that 99% of my shots would be +/- 12fps from the average, which happens to be around 1/4 MOA +/- difference on the target. Will I be able to find a load that has that low of velocity variance with such a huge powder charge? I hope so, time will tell.

For closer in work (500yds or so), velocity deviation has a much smaller effect; the same velocity deviation for the 300grSMK around 3000fps is only 1/10 MOA, so its much less critical.

GG, get to playin the Lotto would ya?

BTW, I think BountyHunters message was in response to CatShooter. At least thats who he replied to with it.

Don

 

[BountyHunter]

GG or anyone else

a ladder simply gets you to a node very quickly and IDs the upper end pressure for that load. At the end of 30 rounds (max) I know my upper limits, at normally at least two (highly supected) accuracy nodes. the most accuract node is also not the highest MV wise. I set up my ladder charges to go over what I suspect is the top end. that way as I go up, I monitor pressure signs, measure expansion and when I get to what is the limit I stop the ladder. I might have rounds left over but I know my top end for that gun.

After that it is standard accuracy reloading techniques to lower SD ES etc. I can normally reduce my group size and ES, SD with tweaking seating depth and neck tension. It think in this thread I said that I start in the lands (once again max pressure) and work out. That way only one way to go and zero confusion.

However, I have switched primers, reshot my accuracy groups and then run a mini ladder to confirm my load is still in the middle of the node. If I am in the middle of the node, I have never run into pressure problems in hot weather later. I can tell you shooting the groups method has run me into pressure problems later.

Sure I could look at a manual (as suggested) go to top end adn go down from there, and shoot 2-5 shot groups and it would take me 60-200 shots to find the same thing and 4x the time minimum. However, I would NOT know where my top end is pressure wise, I might or might not know where my node starts and ends. I just happened to find on group that shoots good that day and it could be on the top or lower end of a node. If it is top end, let it warm up and your accuracy will go to heck and pressure through the roof.

Remember I am using a chrono and a micrometer to monitor MV and pressure by watching the traditional signs, MV jumps and then case expansion.

I have had extra rounds left over from testing (all various weights in the node limits) at 300/400 and shot 1" ten-twelve shot groups with all different charges. Now that would be a great group for most, but that is not the most accurate group possible obviously. Most of the bullets within that node will group together very closely.

At the end of 2-3 short range sessions and max normally of 60 rounds, I have my upper end pressure documented, I know my node upper/lower limits and have tweaked an accuracy load and reshot it 2-3x to confirm MV range, SD, ES and group.

One time I ran into a bullet that would not shoot in a ladder and switched bullets and got what I needed the next time. However, it only took me 20 shots to confirm that bullet would not work in that gun with that powder, not 60-200.

BH

 

[Eaglet]

GG

[ QUOTE ]
Hope I didn't shock you too much my friend!


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Yah... you did... Just kidding! /ubbthreads/images/graemlins/smile.gif

It's a matter of opinions. I do see and agree with what AJ Peacock and BountyHunter are saying. That's all! /ubbthreads/images/graemlins/wink.gif

 

[goodgrouper]

[ QUOTE ]
I'm sure I'll come up with more after a few hours sleep. Thanks.




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I got to this too late as well and need a few winks before anwering your questions. I haven't forgot about it. Will just have to get to it tomorrow! /ubbthreads/images/graemlins/wink.gif

 

[Chawlston]

In short, yes it works and if you find a load that shows promise, do it again on a different day for confirmation (I personally believe that confirmation is the key). There is no need to use up your barrel life switching recipes blindly in an attempt to prove that your recipe samples will pass muster in statistics class. Just remember the process works and if you can reproduce the results independently, you have a winner. The important lesson to be learned is that if the test works for you and you can reproduce (read back it up) similar results a second time, it is not an accident. Reproduce the same results a third time and you have proven your theory for your gun.

I do my ladders differently as I find the top pressure load with the bullet touching the lands and then back off one grain and do my ladders over a chronograph with seating depth changes of .010" vice incremental powder charges. I use an ogive checker and each bullet will be seated within .0005" and the powder charges will be within .02gr. using my precision digital scale. I noticed that once I got the precision scale, the results were easier to backup on a different day. Anyway, my results in my rifles can be reproduced over and over again and I put a lot of faith in them as my hunting plans and setups are based on the ladder and the second ladder as a proof.

Actually, once I find a recipe that works, I try to disprove that it works by attempting to reproduce the results over and over again. Not once has a recipe that worked as best the second time ever failed after that. Bear in mind, that I am after sub .2moa results or I do not stop testing. For me, that is enough as I would rather spend my time in the field than at the bench. My process usuually yields results very quickly and I don't use up my barrel life proving something to satisfy someone else. I think if you tried it, you would like the results.

BTW, my wife is a math professor and she is amazed that winners at shooting matches are crowned with such small statistical samples of shots on target. Once I explained the process of relays and shooting over different conditions on each relay to her, she was a convert. You don't have to satisfy the statistical "gods" find a shooting recipe that works for you.

I am still waiting for her to prove to me mathematically that a bumble bee can actually fly. /ubbthreads/images/graemlins/shocked.gif

Good luck in your testing.

James

 

[goodgrouper]

Grit,

I was going to type up my whole reloading and load finding process step by step for you but then I realized I don't have to. It is much easier to just tell it to you rather than type it! Come see me.

 

[grit]

See you soon.

 

[Slopeshunter]

Goodgrouper,

If you wouldn't mind sometime typing out your method, I would certainly be interested in reading it.

I just don't have the time right now to do a road trip down to Utah /ubbthreads/images/graemlins/grin.gif

Tks!

 

[Eaglet]

GG,
My friend, just because I believe in the ladder test does not mean I'm putting down your experience and knowledge. No Sir! If you ever write your procedure for reloading I'd love to read it and if you were to make a book with it I'd be the first one to buy it! Sure!!! I do respect and honor your accomplishments.

 

[Pdvdh]

Goodgrouper,

I'll pile on here and say I'd also appreciate a post covering your load-development-by-chronograph techniques. In my limited ladder test experiences, I have monitored and recorded velocities with my Oehler chrongraph. I've more or less concluded that a ladder test cluster that also coincides with several consecutive loads with similar velocity (little velocity gain per incremental powder charge increase) is a potentially good powder charge zone, worth further research. And that these two features coincide too often to be purely coincidental. I'm not sure this matches with your (or others) load development experiences or not. As a consequence, when running ladder tests, any clusters of incremental powder charges which yield limited velocity gains (velocity gains hesitate for several rounds before again increasing with each increased powder charge) get my full attention. I load additional cartridges in these powder charge zones while testing for accuracy, ES, and SD. As you have posted more than once, low ES and SD is mandatory for truly long range shooting in order to minmize vertical spread. So if good accuracy and precision can also be attained by developing loads with a chronograph, we kill two birds with one... bullet?