explain Ladder test?

Mag 300

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    First Yes did the search for ladder test best was the 300 wm with the 208 amax.
    what is the purpose of the test shooting one bullet?
    they will string all over . could you explaing the test and how they determine a good round? I am looking for test criteria maybe the ladder test is it ?
    Thanks
    Bill
     

    flashhole

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    Re: explain Ladder test?

    The intent of the ladder test is to show you nodes where a particular powder charge range will provide good accuracy.

    The test requires you have a decent shooting distance like 300 yards. I've done them at 200 yards but the results can be a bit difficult to interpret. The test works but I suggest you do the same test 2 or three times to ensure consistent results.

    In general I usually find two charge ranges where the shots start to clump together and one is always near the top of the load range. Onece the range is identified I do the test again with smaller powder increments to fine tune it. I like the test and I have optimized my powder selection/charge range to work with Lee Dipper Cups. The "range" provides a bit of forgivness in charge inconsistencies and still yields good accuracy.
     

    oldgrayone

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    Re: explain Ladder test?

    Here is a writeup from another site:

    The basic theory is that with the same brass, primer, powder type, and bullet seated to the same lengt. You then load one round at the starting charge (gotten from a reloading manual) then increase the charge .2-.5 grains for the next round and continue loading one round at each weight until you hit the recommended max charge. This should give you anywhere from 9-15 rounds each with a slightly higher charge.

    Next you fire those rounds slowly (so your barrel doesn't heat up) at the same point of aim. 100 yrds is acceptable but I hear 2-300 is preferred by alot of people. For this to work you MUST record the shot placement for each round on the target. When you are done, in theory you will have 2 maybe even three "groups" on the target. For instance shot 5,7, and 9 group tightly with 7 in the middle of the group. This would mean that round sevens powder charge was optimum for the rifles harmonics not necessarly the fastest or most effecient.

    Then load 3-5 more at that same charge and fire for an actual group...theory says it would be the best out of your gun.
     

    Fuzzball

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    Re: explain Ladder test?

    I only have a 100 yard range to use. So, to prevent ambiguity, I tack up about 6 targets at a time and number them. Each target gets ONE bullet. After completion, I stack the targets over a final target and mark the bullet holes and number them for the record. It's really easy to find the node ranges and be certain I haven't misplaced a hole!

    Well, I've recently started loading TWO rounds of each charge and fire both at the same target. That helps avoid some anomilies that were occuring previously. If any two holes are close together it can be a fluke, if they are far apart it's NOT a fluke, and the "ladder" steps are still vailid.
     

    frzburn

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    Re: explain Ladder test?

    Well you can shoot them all the the same target, as long as you record where each shot landed. (i.e. someone in the target pit, or a spotting scope)

    The ladder test is all about barrel harmonics. It's to find a load that will make the bullet exit the muzzle when the muzzle tip is on a peak (either top or bottom) of the vibration curve.

    Too bad, I had a link for a Website that explained it all in details, but it doesn't work anymore... Here's the link anyway, if someone is able to trace back the old content: http://www.lima-wiederladetechnik.de/Englisch/Laddertest.htm
     

    hunter81

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    Re: explain Ladder test?

    Make sure you use a digital scale, .2 to .5gr increments need to be accurate
     

    shoepop

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    Re: explain Ladder test?

    This ladder test has been confusing to me, no surprise there. I loaded up 2 rounds of each powder weight all else the same. I started @ 125 increasing .4 grains to 126.9. I fired 1-6 and then another 1-6. As powder weight increased groups tightened up CONSIDERABLY. My question no pressure signs on highest weight load should I keep increasing or now work on bullet depth? I
    still don't know if done correctly but it did produce results that helped me after chasing my butt for a month.
    DSCN3658.jpg


    7/7/09
    Result's after bumping up powder today. No vertical movement, never encountered sticky bolt only VERY light ejector marks @ 128 grain's. Can I assume this is all I'm going to get out of this powder velocity wise? I did seat bullet just touching lands this go around 1'st time I had them jammed pretty hard into lands. Now if I'm interpreting the data correctly I have a sweet accuracy node from 125.5-127.3 correct?
    DSCN3668.jpg
     

    steve123

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    Re: explain Ladder test?

    Mark,

    I've found that my big gun shoots best with loads that are just less than max.So before doing a ladder test I find out when the bolt is getting sticky and back up from there.Saves some time and components.Also with R-25 the load density is better with a warmer charge and helps with ignition issues.

    Is it a 408 or 375?

    Steve
     

    kyreloader

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    Re: explain Ladder test?

    I dont believe #7.

    I would shoot again, going up in charge. I would also shoot two targets with increasing charges and see if a pattern starts.

    Good shooting at 500 y.
     

    Mag 300

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    Re: explain Ladder test?

    so the idea is lo load one powder / bullet series shoot them at say 300 yds and the one that hits the highest matches the nodal plave of the barrel the best?
    Bill
     

    steve123

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    Re: explain Ladder test?

    Bill,

    Usually what happens is:
    Say you start at a low charge,4 grains below max and load rounds in .3 grain increments.Then you shoot them at 300 yards,working your way up to max,there will be a small number of shots(a group)or even(two)that are together close on the vertical plane.These would represent one or two nodes to choose from.I pick the middle of the higher node because I want as much velocity as I can get and I get better load density that way also.

    Then I take that load and go .1 grain more and .1 grain less to see which shoots better of the three.Then I start adjusting the seating depth till I find which depth gives the best groups.

    Here's a pic of a recent ladder test with my 6mmART40 with 115DTACS at 315 yards.
    The three shots circled are shots 11,12,13 which are .2 grains apart for a total of .4 grains.So I would have picked shot #12 to work up a load with.The velocities were too low,only 2675fps,so I decided to stay with the 105's.

    See how the shots ascended from the bottom then stopped at those three shots and then proceeded to go up as the pressures rose.But as you can see when you find a node the groups start shrinking.
    The shots off right of the orange dot are from another ladder test from another gun so they are not included.
    DSC00179.jpg


    Steve

     

    Greg Langelius *

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    Re: explain Ladder test?

    My ladder testing is peformed on a series of rows and columns of 1/2" yellow dots with bold black ring outlines at 100yd. One shot only at each dot, and five to fifteen dots per charge increment. I keep an identical target at the bench, and comment and annotate upon it as I fire each shot on its counterpart downrange. This may appear excessive but my intent is to relegate chance to the bottom of the set of circumstances on the basis of importance. The single shot per dot concept eliminates a lot of doubt and/or confusion.

    Right now, I am refraining from doing any new development and ladder testing because of the impact of the artificial shortage of components on my stock of handloading supplies. I have loads that work with the guns I'm currentkly using for comp, and I'm really not under any great compulsion to develop loads, at the moment, for guns I have rececently acquired.

    My shooting partner is playing with a recently acquired Deuce of mine, using as stock of bullets and powder derived from some unsuccessful experimental .223 loads that were broken down for components. It keeps him happy and it serves a useful purpose.

    Beyond that, my development work awaits better times, the bulk of my shooting is done with .22LR, and I only produce and use 50 rounds of .223 comp ammo from a proven load recipe; when and as needed for FV200 Comp twice each month.

    Greg
     

    steve123

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    Re: explain Ladder test?

    Mark,

    IMO 127 to 127.5 grains looks like a good zone.Your gun is shooting good.What FPS are you getting?

    Steve
     

    shoepop

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    Re: explain Ladder test?

    <div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: steve123</div><div class="ubbcode-body">Mark,

    IMO 127 to 127.5 grains looks like a good zone.Your gun is shooting good.What FPS are you getting?

    Steve </div></div>

    That's in the range I was thinking Steve thanks for the confirm. I haven't chronoed RL25 yet was playing with some slower burning powder that didn't work out. My come up from 100 zero was 6.25 MOA @ 500, all were centered around 2" aiming circle. The RMB 420 grain I'm using has a claimed BC of .893 I need to plug that in and see what it guesstimates. It was over 100 degrees today, I'm at 4600 ASL uncorrected so air was pretty thin.
     

    shoepop

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    Re: explain Ladder test?

    Shot @ 1000 today with 127.5 RL25, 420 RMB jacketed seated to just kiss the land's. Results were not great, I shot 4 5 shot groups worst 18" best 15". Vertical was ok 6.5" max, horiz 18", wind was not a factor. I'm having trouble with trigger finger placement/pull with the Windrunner AR type pistol grip, it sucks even with a good 1.5# trigger. I need to dry fire and see if I'm inducing the horizonatal movement. I did get real time elevation data @ 108 degrees, dens altitude 8247' I needed 19.50 MOA from 100 zero. Going to repeat with same load and also load some 419 copper solids over same 127.5. Since the vertical was ok I'm thinking the 127.5 node is a good one, my thinking correct?
     

    steve123

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    Re: explain Ladder test?

    Hi Mark,

    Don't get discouraged.Ladder testing is just the first step to tell you where a good place is to start actual load development.

    Unfortunately I kept having to adjust seating depth and powder charge until I finally found what the best load was.It's time consuming and costly but worth it.Soon you will find that combination that works!

    At this point it might be a good idea to load 3 rounds each at 10 thou increments away from the lands and see which ones shoot best.

    Steve
     

    EricF517

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    Re: explain Ladder test?

    Ok I think I understand the ladder test somewhat. So you guys let me know if my thinking is correct in the following pics. One is a ladder with Varget and the other with 4064 in Fed brass with Fed match primers under the 155smk palma.

    Varget:
    miscpics09196.jpg
    I was thinking something with 13?

    Here are 12 from the 4064 batch. I was thinking of #7 or #10. Using the numbers starting with the top left to right to middle left to middle right........

    Erichshootingandcass002.jpg

    Erichshootingandcass003.jpg


    I am going to rebuild the last two tomorrow and shoot them when I have more light. It was dark to the point the dots were hard to see.
     

    TomS308

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    Re: explain Ladder test?

    What they call the Ladder test nowadays.. i used to call working up a load 30-40 years ago.. Starting at the min. load.. and working up to max.. in .5 gr increments.. Some where in between you will get a group smaller then the others.. But i buy a cartridge for a certain level of performace i am seeking.. i have no interest in shooting a 300 WM for example, if the best grouping is at 308, or 30-06 velocities.. i am only interested in shooting at the velocities the cartrdge was designed for.. To many people are obessed with bench grouping.. Yet in real life field shooting.. it makes no practical deference.. i`ve seen shooters regularly shoot under 1 MOA off the bench.. but get them out in the field.. and they cant hit the side of the barn..
     

    Farnes Williams

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    Re: explain Ladder test?

    The ladder test is a great way to find the best load for the least amount of shooting, but it does not matter if you do the ladder test ten times with a powder and bullet your rifle does not like. You first need to find a load that your rifle shoots reasonably well and only then will the ladder test speed the process up. Just be patient and take your time shooting or it will all be for not.