Load Development: Ladder Test

Discussion in 'The Ammo & Reloading Forum' started by JLA, Oct 24, 2011.

  1. JLA

    JLA Well-Known Member

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    From time to time we get on the subject of load development here at TFF Ammo and Reloading Forum, and I always recommend the Audette Ladder test to anyone asking my opinion on the best load development method. Its the method I use because its faster than the conventional method of loading 5 at each increment and shooting the groups, its just as definitive, and it saves valuable ammo. Here is a link that describes exactly what the ladder test is and how you use it to develop a load for your rifle or handgun.

    http://www.desertsharpshooters.com/manuals/incredload.pdf

    I have my own method of doing the Ladder test. Instead of shooting one POA on one target and recording the individual POIs on a separate sheet, I decided it would further simplify the process and eliminate the need for recording where the shots hit on a shooter copy of the target by making up a master sheet (quite large of course) with 20 separate targets on it. Labeling each individual target with the number of the shot and the load it contained. Of course you do all of this before shooting the test and set it up so you work from left to right, and top to bottom. Here is an example of the test i fired today with my savage .308 at 200 yds.

    Attached Files:

  2. JLA

    JLA Well-Known Member

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    I used a sheet of poster board 28"X22" which works out to 20 equal squares 5.6"X5.5". This is more than adequate if your rifle shoots MOA or better, and would also work great for pistol load ladder test development at 30 yds or so.

    Notice on the sheet that it appears the rifle would shoot just about any load within the data range acceptably. It is afterall a very accurate rifle. But look at shots 14-18, and notice all 5 of those fired at the same target would have clustered into a nice sub 3/4 inch group at 200 yds. That gives me a sweet spot in the load data from 46.5 gr to 47.3 gr of Alliant 2000MR. Which is a pretty broad sweet spot. Deciphering this data is simple. You take that spread and load the charge in the middle of it, that gives you an ideal charge weight that allows variances both above and below to group along with it. According to this ladder test my rifles ideal load with this combination of components is 46.9 gr 2000MR. I am going to load the remaining 29 pieces of new brass with that 46.9 gr and go shoot some groups at 200. If the test told the tale correctly I should get at least 3/4" groups at 200 with it.
    Last edited: Oct 24, 2011
  3. Chinook

    Chinook New Member

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    Nice! Thanks for puttin all this together Josh! Makin life a lot easier for me as I get into this re-loading game. Cant read, or re-read enough of your posts man. Again, thanks for all the input you give us!
  4. JLA

    JLA Well-Known Member

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    happy to do it. I wish there was readily available info like this when I was first starting out. It would have saved me oodles of ammo.
  5. jack404

    jack404 Former Guest

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    good one Josh i made small notes only , now have to figure them out for folks , this is a way better idea
  6. JLA

    JLA Well-Known Member

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    I think so too Jack. Up to now i have been doing it the way described in the link above. But this morning while setting up it hit me. So I ran down to the DG in town and grabbed a posterboard and some sharpie markers. Already had the Direct hit stickies in the console of my ford. Used a tape measure to mark off the squares and a slimjim as a straight edge. Had the whole target outlined, labeled and ready to shoot within 10 minutes. Only waiting around I had to do was 3 minutes between shots.

    I already had a half box loaded in old brass with a mid range load. Used that to get the scope set to hit 2 inches right at 200. then cleaned the bore and fired 5 foulers then a 3 minute cool down before starting the test, and 3 minutes between shots. All in all I knew what my load was going to be within an hour. And todays conditions couldnt have been more than ideal. It was dead calm, no mirage, and the high today was just shy of 80 degrees. This test was shot this AM at around 11 or so, the temp was in the low 70's. And every shot felt perfect. i didnt pull a single one and the trigger broke exactly where i wanted the crosshair to be. truly some of my best shooting this year I think.

    Rifle was rested on sandbags and we were comfortably seated at my solid bench.
    Last edited: Oct 24, 2011
  7. Claudius Valarium

    Claudius Valarium Member

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    Thanks for the post Josh. Sometimes it's good to think outside of the box. I'm getting ready to do some ladder testing on 22-250 loads and this looks like an easy way to get it done.

    A variation on this idea would be to graph out two targets on 8 1/2" x 11" paper or four targets on 11" x 17" paper - these can be put into a three ring binder for reference later.
  8. JLA

    JLA Well-Known Member

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    that would work the same if you wanted to keep a data folder on it. I keep a notebook and hang targets like this on the wall in my reloading room.

    I loaded the rest of the brass last night and im going to shoot some 200 yd groups with it. todays conditions mirror yesterdays so I should get the same results.

    Ill shoot an SBGO card for you Jack. :)
  9. reynolds357

    reynolds357 Former Guest

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    It is a good idea. I will have to try it. I always play with seat depth before I play with powder charge.
  10. JLA

    JLA Well-Known Member

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    I use a generic seating depth of .010" off the lands for bolt actions and maximum listed COAL for semi-autos. Once I have obtianed a good load I then adjust the depth in increments and test them. Almost always end up within .005 of the original .010 off if not .010". thats the figure I find that works best in most rifles.

    Semi autos are different. I have found they sometimes like the bullets waaaay off the lands to shoot well.
  11. reynolds357

    reynolds357 Former Guest

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    I have found that a rifle likes what it likes and have found no other correlation. I start with the bullet jammed into the rifling and back up from there. I have a 6.5 X 55 Swedish Mauser that will only shoot 140 Bergers if they are actually pushed deeper in the case by the rifling themselves. It shoots a ragged hole that way. If you back it off ANY, then it is 1.5 moa. The only negative is that once you press down the bolt, you have to shoot it or dump powder out of the rifle and knock the bullet out with a rod.
    Last edited: Oct 25, 2011
  12. JLA

    JLA Well-Known Member

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    Here ya go Jack. It was a bit too gusty for group shooting beyond 100 today so I just chronographed the .308 loads and didnt bother with fighting the wind. But I did shoot you a SBGO card at 50 yds with my M1 Garand. 8rds to the 'ping' :)

    Attached Files:

    Last edited: Oct 25, 2011
  13. JLA

    JLA Well-Known Member

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    Alright guys. Heres something else I found rather interesting and useful charting a Ladder Test on a large sheet the way I illustrated above.

    I graphed the POIs in the paint program with a blue line and you can see the barrel vibration on the paper from shot to shot. kinda like an ocilloscope still. or waves on the ocean. and notice how straight the curve is from shots 14-18 and then how it goes right back into a sharp whip at 19 and 20.. A recoil vibration pattern graphed on paper. How fascinating is that.. :thumbsup:

    Im liking this alot. :)

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  14. JLA

    JLA Well-Known Member

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    My wife just pointed out a fantastic point...

    My aiming points werent 100% perfectly lined up so iIalso plotted them from bull to bull to illustrate the bore at rest. The line (in red) represents the rifles bore at rest while aiming. The blue line represents the bullets release point during the barrels vibration cycle. Note how at first every other shot was at the top of the cycle and every other shot was at the bottom. This profound difference from shot to shot can only be explained by the lower muzzle velocity, and as the velocity increased the profound 'peaks and valleys' turned into flowing waves that cover 2 or 3 shots at a time until the load hit that 'sweet spot' where the bullets were exiting the muzzle while it was at or near its rest point, then resumed the resonance pattern.

    Thanks my dear.. :)

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  15. JLA

    JLA Well-Known Member

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    That seems common to long leade milsurp rifles. Almost all the milsurp bolt actions i have tinkered with preferred a good jam. Problem with some is the leade is so much theres barely any case on the bullet. My finn 39 comes to mind. Itll shoot ragged holes if i seat to the lands with a 174 SMK, but any less and it quickly spreads the groups out. So i seat em where the rifle wants em and put a fair crimp to keep the bullets still during loading and feeding.

    I also had a British enfield #4 mk 1 .303 that wouldnt shoot unless the brass was necksized ONLY, and had at least .2" of jump. Dunno, what the deal was with that one. I must have wasted 1000 bullets and 3 pounds of powder trying to figure it out.
  16. woolleyworm

    woolleyworm Active Member

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    Very informative thread, thanks for doing all the bench work Josh ! I'll give this a try next time and see what I can add to it.
  17. Chinook

    Chinook New Member

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    AW, dang! This is great info!
  18. reynolds357

    reynolds357 Former Guest

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    Unfortunately, there is not enough bullet left in the neck to crimp. This rifle is a new CZ 550 American. It will shoot other bullets seated deeper, but not the berger. Unfortunately, it won't shoot anything as good as it shoots the berger. Its favorite powder just happens to be supreme 780 filled half way up the case neck. There is so much of it, that you get hit by unburned flakes coming out the muzzle brake. But having said all that, it is a tack driver with that dysfunctional load. I have also observed the same thing you mentioned in military surplus rifles. My theory is that the riflings are set way back to handle the round nose ammo the european nations fed them.
    Last edited: Oct 25, 2011
  19. JLA

    JLA Well-Known Member

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    thats what Ive read too. In fact if I didnt have such a soft spot for milsurp weaponry I wouldnt even bother with them.. ;)
  20. JLA

    JLA Well-Known Member

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    Thanks worm! Only problem I have now is my wheels are turning and I dont have anything else to ladder test. I need to go ahead and order my .243 barrel for my rem 700 and get that thing finished so ill have something else develop a load for. :)
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