Audette ladder test questions

Discussion in 'Long Range Hunting & Shooting' started by Topshot, May 26, 2009.

  1. Topshot

    Topshot Well-Known Member

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    I have been playing about with ladder testing and have a number of questions.

    1. What distance is the most popular distance to shoot a ladder test?
    200yds, 300 yds, 500 yrds, 1000 yds?

    2. Single shots of a particular powder charge or multiple?

    3. Charge increment?

    4. With a new, unfired rifle how many shots would you run through it prior to doing a ladder test?
     
  2. royinidaho

    royinidaho Writers Guild

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    That's what I do. Hope it helps.
     

  3. MontanaRifleman

    MontanaRifleman Well-Known Member

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    I have approached this several ways and I am by no means an expert.

    It depends.....

    If I'm shooting a new barrel, I'll use my load development to break it in. I might load 3 shots ea, beginning with the starting load and clean after each shot that probably wont give me a good feel for the accuracy of that charge but it might get me a rough idea for accuarcy and velocity and I am getting my barrel broke in. I have never to date settled on a starting load as the pet load for that rifle and cartridge. By the time I get to near max loads, my barrel may be broke in and i can start shooting for groups 3 or more at a time to find a good charge, then fool around with the seating depth.

    Another method I have used is to load up 4 rounds for each increment and shoot one at a time while climbing the ladder until I find my max. Then, beginning with the max load, I'll shoot the other three shots (4 shot groups) and work back down looking for the best

    I'll usually start at 1 gr increments at the lower charges then switch to .5 gr increments when I think I am with in 2 or 3 grains of max.

    Bottom line is I usually come up with a plan to fit what I want to accomplish in the best and most efficient way I can, especially if resources like bullets, powder and primers are slim.

    And I always do my load development at 100 yds... not sure if that's the best way, but it's easier to see the bullet holes and less enviromental factors affecting the groups.

    That's just me.

    Regards,

    -MR
     
    Last edited: May 26, 2009
  4. BountyHunter

    BountyHunter Writers Guild

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    300-400 Yds, no further.

    No wind condition in the evening and mornings is critical.

    one shot at powder increments already stated. I start VLDs about .020 into lands and non VLDs about .020 off the lands.

    Chrono is essential! You will have not only POI groupings but MV groupings. it will be easy to see where the MV stops jumping and groups and then starts jumping again. They normally coincide with the POI groupings.

    I start final load development in the middle of the nodes with tweaking powder and then seating in 3 shot groups. May vary neck tension if bushing die.

    Wildcats- drop 10% from recommended load and work ladder as normal. Chambers and individual barrel differences can bite you unless you do that.

    IMO rifles should be broken in before testing.

    BH
     
  5. AJ Peacock

    AJ Peacock Well-Known Member

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    BH, you and I are almost identical in our method. I use 200yds though and rely on the velocity as much as the impact points. I'll hang 6-9 targets so I don't need to continually go downrange. I'll then graph the vertical distances in Excel for each shot (I ignore horizontal, because wind is always an issue for me). I'll also graph the MV for each load.

    I'll calculate the additive change in vertical displacement (in MOA) and MV difference across each successive 3 shot's which will show me nodes in both MV and vertical impact points. For example, I'll take the vertical difference between shots #3,#4 and shots #4,#5, add those differences together and use that as my shot #4 number. Here is a picture of an excel spreadsheet I did a couple years ago.

    [​IMG]


    AJ
     
  6. Fiftydriver

    Fiftydriver <strong>Official LRH Sponsor</strong>

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    I have a question for those using the ladder method for load development. I am not trying to pick any type of a fight, I just want your experience because I do not use this method any longer for one specific reason and I will expound on that in a bit.

    How many of you have performed a ladder test on a certain day and then repeated that same ladder test several times on different days?

    The reason I ask is because I did try ladder testing several of my rifles several years ago. Before that I always just shot groups at long range to find the best loads for my rifles. I figured with all the buzz about ladder testing I would try it.

    One was with a 257 STW. Ran through the test pretty much identically as discribed above and came up with what I felt was a great load.

    I used that load for a bit practicing at long range and I was never really happy with the consistancy, it was good but nothing special. So, I went back to my old method of shooting groups at long range and before long, I had several loads that were holding 1/2 moa or less at 500 yards. The load from the ladder test was averaging around 3/4 moa, good but nothing special and not what the rifle could do.

    This made me curious. The loads I was getting the best accuracy and consistancy with were not the loads that the ladder test showed would be the best choices....... This just confused me. I wanted to give the Ladder test a good honest go so I did it again.

    If I looked at the two ladder tests side by side you would have never known they were out of the same rifle......

    Cleaned the rifle thinking that may have been the problem and tried it again, same results, totally different then the other two tests.....

    Now this was a sporter weight rifle with a light contour 30" barrel. I was shooting the 130 gr Bonded Core HP Wildcat bullet. Ladder test #1 said that the best load would produce around 3380 fps. Test #2 showed that it looked like around 3430 fps was best. Load #3s best results looked to be around the 3350 fps range....... This totally blew me away and that was the last time I used the Ladder test.

    I went back, loaded up some ammo until the cases started to show very slight pressure signs and then backed off two full grains. Velocity average was 3480 fps and three shot groups at 500 yards averaged Just under 2" at 500 yards center to center for five three shot groups.

    Tested on different days, if conditions were good, that load would always produce sub 1/2 moa groups at 500 yards while I could not get that consistancy with the Ladder test loads.

    So, my question has always been, has anyone done repeat ladder tests on several different days to see of those tests repeat themselves time and again? Or do you just run the test once, take the best load from what that test shows you and use that load without question?

    I just have not had that much luck with the Ladder tests. It may have had to do with the extremety of the chambering I was using but I had no problem getting 1/2 moa consistancy the old fashioned way.

    Just curious what you guys are seeing when you compare ladder tests for same rifles and loads on different days. Do they support each others findings or do they very from day to day?
     
  7. BountyHunter

    BountyHunter Writers Guild

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    IF you get the node correctly ID'd it is repeatable time after time. To me, the key is to insure that I have got a POI and a MV node, when that happens repeatable is never an issue. All that does is ID the node and you still fine tune from there with both powder and then seating depth.

    I just posted under reloading forum a link to an article and video by Jason Baney over on 6br.com that is really good. Jason does it a little different but works the same.

    BH
     
  8. AJ Peacock

    AJ Peacock Well-Known Member

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    Kirby,

    To answer your question, I haven't run the same test on different days. I would expect the velocity information to line up better than the point of impact info. I put more emphasis on the velocities than the point of impacts.

    I look at the results as 'areas to try' and have had very good luck when using it in that way. Another way to look at it is that the results have shown me loads NOT to use (drastic swings between increments). The ladder tests I've performed have all resulted in loads that shoot 1/2moa or better, which might not be the 'best' possible loads, they are loads that easily meet my requirements.

    I expect that with a quality rifle and chronograph, I could perform a ladder test and pick a good area with just the velocity measurements. Then check the ES/SD and then see how it shoots at LR. Statistically it would probably be just as good.

    When I decided to try RL-22 for the first time in my 7RM, I did a ladder using RL22/160AB. I found AND verified a load with 24 rounds using RL22 (14 shot ladder and two 5 shot groups). The velocity spread across the node added up to 14fps and the total POI spread was .5moa (average .25moa). When I verified the load at LR, it shot sub .2moa! Maybe I got lucky?

    I might have found this load using other methods, but I'm sure I would have shot more rounds to do so. I had a similar experience when I worked up my first loads in a Savage 300WSM. 1/3moa load in around 20 shots!

    In the end, any process that is used consistently on quality rifles is likely to give good results.

    I find the ladder method good at giving me a process oriented way of quickly understanding the performance of a powder/bullet combo.

    AJ
     
  9. Fiftydriver

    Fiftydriver <strong>Official LRH Sponsor</strong>

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    Very interesting, thanks for both responses. Hope this is not taken as a high jack but as more questions on the same subject.

    Have either of you noticed thats its harder or easier to find nodes depending on the type of rifle used? Such as light sporter rifle compared to say a heavy bench rifle?
     
  10. AJ Peacock

    AJ Peacock Well-Known Member

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    I have more experience using the ladder with the lighter contour rifles and have had no trouble. The 338AM you built for me is my only 'heavy' gun. I didn't ladder test it, I played with the seating depth on the starting load and left it there!

    The heaviest rifle I've ladder tested was the Varmint Contour Savage in 300WSM with a Joel Russo stock (13#'s). My 7RM is 8lbs all in (including Bipod). The lightest I've done is a 6# .243 Win, Rem 700 ADL.

    The .243 (with it's super light barrel and high velocities) had the wildest swings on the target, the 300WSM (Varmint contour) had the smoothest steadiest vertical climb as the powder was increased. I'd guess that the heavier the barrel, the easier it is to 'decode' a ladder test. Probably has a lot to do with barrel harmonics.

    In the article on 1000yd ladder tests, he said that at shorter distances, nodes can completely overlap each other. This would definitely make reading a target more difficult.

    AJ
     
  11. BountyHunter

    BountyHunter Writers Guild

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    to me, I have seen that the rifles must be capable of sub MOA or it looks like "patterns".

    Second thing is that by using the chrono with the process and logging MV of each shot, the coinciding nodes are easier to spot.

    I have found that anything under 300 you can run into overlap with a very accurate gun many times, therefore my insistence on shooting 300-400 and in "no wind" conditions early in the morning or just before dusk normally.

    I will often go down and check the target to number each round fired. I take a minimum of one minute between shots so I have the time anyway.

    I use a plain piece of paper to plot each shot as I shoot it at the bench and number it. I write the number of shots fired on the side (say 1-15) and put the MV beside that corresponding number. When I go down, I will verify each shot placement and number them on the target. At the end, I can take the plot sheet, veryify placement on the target, look for POI nodes and then look for MV nodes and correspoding intersections. It is quite easy normally to see the MV nodes also, for ex

    Once I get a node in the MV range I want, I then start the fine tuning process from the middle of the node normally tweaking powder, then seating depth and last if necessary primer changes. I do not like to make primer changes as normally you need to start over.

    BH
     
  12. Fiftydriver

    Fiftydriver <strong>Official LRH Sponsor</strong>

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    THank you for your replies again. I may have to give the ladder test another try, maybe with a more conventional chambering to get the hang of it.

    I can see how the accuracy of the rifle would greatly determine if a ladder test could be usible, as well as range, conditions and of course shooters ability. In a perfect world, I would think that being able to clamp the barreled receiver into a shooting fixture would be ideal but not everyone has access to something like that.

    Thanks again for the replies.
     
  13. MontanaRifleman

    MontanaRifleman Well-Known Member

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    This question isn't directed just to Kirby.

    Would this really be ideal? Would clamping the rifle or barreled receiver into a shooting fixture cause the rifle to have a different shooting "dynamic" then off a rest? Would you get different nodes?

    -MR
     
  14. Fiftydriver

    Fiftydriver <strong>Official LRH Sponsor</strong>

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    I believe it certainly would change the dymanic of a rifle system to some degree but I am not sure there would be any other way to eliminate the humane element which is the weakest link in most rifles accuracy potential.

    But, as you mentioned, it would be nothing like shooting the rifle off a human shoulder and as such, things would change, especially point of impact more then likely.