THE RETURN OF THE SON OF LADDER TESTING

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  • Last Post 18 March 2009
CB posted this 30 November 2007

Ladder testing is based on the notion that as powder charge increases in steps, bullet impact points rise-until around the “best” load where elevation remains ~ constant, then rises again.

My question was: Does ladder testing work at 100 yards with cast bullets.

I've been waffling about this; looking at my targets and Dan's, and now have decided.

Ladder testing doesn't work at 100 yards with cast bullets.

Even though in the middle 3 tests I thought I could pull some info out.

I've done 10 tests, that's enough for me, for now.

Any objector is expected to have data.

I have my targets and a box to fit them, and will gladly send them to anyone wanting to see them in person.

I wish it worked. I think that's why I tried to interpret them so hard.

joe b.

 

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billwnr posted this 30 November 2007

Dan's results seemed fairly easy to interpret. Your first ones were less intuitive to me.

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CB posted this 30 November 2007

I think you are right Joe. If you look carefully enough and want to see something in data that is random or near random you will see it but that doesn't mean that it's there.

I think the fallacy of ladder testing is that it depends on pretending that the indivdual shots reprent where that particular load will shoot on a vertical scale.

Dan's presentation was great and his preliminary five shot group shows why pretending that those individual shots in the ladder test DON'T represent where it will shoot time after time. One of those bullet strikes that make up a possible sweet spot may actually be the highest hit in a group - if groups were being shot.

I think this is another case of trying to get more information our of too few data points just like deciding one load is better than another on the basis of a couple of pairs of five shot groups with a ten percent size difference.

Interesting topic though and the data presented made us think.

John

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CB posted this 01 December 2007

Joe You are expecting alot here. You may have ten tests, but what is the test? A ladder test with what criteria?

I do a somewhat modified ladder test, I shoot groups, 5 shot groups, 3 foulers always start with a clean barrel. I use a standard CBA score target, that gives me 5 bulls one sighter target. I load at the range using a scale to verify each charge. I usually increment in .5 gr increments in each group until I find the tightest possible pattern, then I repeat the group test in .1 gr. increments, repeating the smallest group several times.

Then is the ultimate test, I shoot the load in a match to verify.

Does it work, do I have data... Sure, just look at my match results for the past 3 years, I don't embelish my tech data sheet at all, I tell what I do.:^:

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shooter93 posted this 01 December 2007

Thank you for the apology Joe...and I'm sure I speak for pat too on that.

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CB posted this 01 December 2007

Jeff Bowles wrote: Joe You are expecting alot here. You may have ten tests, but what is the test? A ladder test with what criteria?

 

We now know what is said to happen as powder charge goes up. The test is to see if that happens. I don't see it happening, and I looked real hard. This is all at 100 yards at low velocities.

Maybe it works-probably does if we can believe the proponents-at 300 yards with jacketed bullets.

But it doesn't work at 100 yards. I wish it did.

What you're doing doesn't seem to have much to do with Creighton's original thesis; nor does what I've tried at 100 yards.

joe b.

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CB posted this 01 December 2007

I played with the Creighton concept for a whole summer at 100 yards. The problem I had was that the difference in the vertical string that was supposed to go higher and slightly right of point of aim was that it was much smaller than I anticipated. However it does do what he indicates it will do. I observed a ragged one hole 10 shot group that went from center to the upper right. However that was all I could glean from the target, as for locating 'sweet spots' at 100 yards, that was almost impossible. Not because it doesn't work, but because there was not enough spread on the shots due to the close distance from bench to target.

It would be interesting if there were a way to do single shots at a target and overlay them or to find a computer program that could scan and compute the location of the bullet hole in each and tell us this type of info... I think the ladder test works, but these tired eyes just can't see enough detail to prove it.

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CB posted this 01 December 2007

Jeff Bowles wrote: I played with the Creighton concept for a whole summer at 100 yards. The problem I had was that the difference in the vertical string that was supposed to go higher and slightly right of point of aim was that it was much smaller than I anticipated. However it does do what he indicates it will do. I observed a ragged one hole 10 shot group that went from center to the upper right. However that was all I could glean from the target, as for locating 'sweet spots' at 100 yards, that was almost impossible. Not because it doesn't work, but because there was not enough spread on the shots due to the close distance from bench to target.

It would be interesting if there were a way to do single shots at a target and overlay them or to find a computer program that could scan and compute the location of the bullet hole in each and tell us this type of info... I think the ladder test works, but these tired eyes just can't see enough detail to prove it. It may just be that the range-100 yards-is too short. Maybe it would work with CBs at CB velocities at 200 yards, but there's no 200 yard range closer than ~300 miles.

I'll try to get some experimenters to try at 200 yards.

I guess that my criterion for success is looking at the target and seeing IT. If it takes analysis, maybe it don't work.

The targets I've seen have the characteristic that one immediately sees IT, or at least I do.

Anybody for 200 yards?

joe b.

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Ken Campbell Iowa posted this 01 December 2007

Hi Joe, I dont think 200 yards is much different than 100 yards. maybe worse, because now you have 200 yards of wind swirls to work thru.  unpredictable wind swirls....

I think AlexanderJ has it pretty much nailed ... the one shot just doesn't define the impact of that load very well ...  in general, I think that the one bullet hole is somewhere in a circle of about twice the diameter of an average group of that load.

Dan's fine rig was giving 5 shot groups of about 1 inch, so any one shot I suggest is somewhere in a 2 inch circle drawn around it.

The fact that his ladder shooting seemed to walk according to the powder charge, while terrific to see, is probably something like drawing a straight in poker ... ie not very likely, although I seen it with my own eyes.


Also, the ladder thing is complicated by the effect of both how ” good ??? ” the load is, and how well the load matches the “tuner” sweet spot.

I believe that the * ladder * thing is probably more related to going thru a Tuner sweet spot than actually falling into some magical ” good load"  .... 


Going back thru the years of Precision Shooting, and yes Fouling Shot,  me of the I Believe In Tuners Club ..... (g) .....  have to wonder how many very complicated and time-consuming tests were done in ignorant ( ie not experienced ) bliss of not even knowing about tuning barrels ...

Just finished reading for the 8th time * Bullets Flight * and Geepers if they had only known about tuners ... and especially if Dr. Mann had had a Vic 20 to sort data with ....  Even Harry Pope gave Dr Mann “heck” for not trying different loads ...


Since your adandonment ( justified ) of testing ladder theiry, it would be good if you thought about::

Which is better... a mediocre load that is right in the sweet spot of a tuned barrel.... or a really great load which is not in the sweet spot..... or could even be in the worst tuned match with the barrel ...

Now THAT would be a world-class project, a guy should be able to put that on a spreadsheet somehow .. OWCH.. there is that migraine again.


Hey I just got in a Lee Special order 22 mold, a ” 22 Bator .. real cute, a blunt little thing, maybe I will cast with it and that rcbs to see how they compare.  Anybody want a .22 Bator, I bot a couple extra to hustle the special order aong.  off forum if you are interested.  I hope to cast some yet today, won't get to shoot them today tho.

regards, ken campbell, ” Iowa in the the Ice"  

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shooter93 posted this 01 December 2007

Two hundred yds. does show up a bit better with the “but” being...higher velocities and near perfect wind conditions. The 2000 fps and up seemed to work slightly better but I'd want to shoot more groups than I have at that range using that method. I have two rifles in the works for the 2200 fps range so maybe in the Spring i can use them. I have 4 ranges within an hour of me that allow me to shoot 200, 300 on 3 of them and to 1,000 yds on the 4th so that's not a problem for me. Winter is firmly entrenched now though it seems so it may have to wait till Spring. It's possible i can finagle use of a heated shooting area near me but maybe not.

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CB posted this 01 December 2007

Ken I would put a picture or something of that mould in the wanted to sell forum.. There are several 22 shooters lurking about.

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jo191145 posted this 07 September 2008

First off let me say I know diddly about shooting cast bullets. I stumbled upon the threads in this forum while looking for the original Audette Ladder document that used to be posted on the web. Out of curiosity I read them anyway and was surprised at some of the negative comments. Every load I ever developed was from an Audette ladder. No, they're not always perfect but neither is conventional load development.

If you want to shoot a ladder at 100yds it is possible. I've done it for the 204R and 308Win. (mostly for fun) You will need to change things a bit though. Do not use one single aiming point. Instead print off some web targets with twenty or so dots and grid lines. Make extra targets as its not always useful to use each dot. As the bullet climbs it can get a little confusing.

Fire one shot at each dot and record the POA(dot + charge #) and POI on a duplicate target on the bench. If I can easily see the nodes with a 204 you folks should easily see them going half the velocity.

I would consider this method a hybrid between Audette and Newberry.

200yds is better though. Good Luck.

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LWesthoff posted this 14 September 2008

Couple of years ago I picked up some 4227 at a good price and decided to try to work up a good load for my .308 Savage 12BVSS and 311299 cast bullets.  Started around 19.0 gr. and went up in half grain increments.  At 100 yds. the 5 shot groups went down, consistently, with every half grain increase in powder charge.  I thought about that for a couple of days, re-read Joe Brennan's book which said the POI would climb with every increase in charge, and then I repeated the test - with three shot groups this time because I was looking for POI variation instead of group size - and verified that my previous results were, in fact, correct.  I decided that in that instance, at least, Brennan had repeated something he read or heard rather than something he had actually experienced, and I went on to more productive pursuits.

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jo191145 posted this 14 September 2008

L

A ladder test does not consist of 5 shot groups.

The fact that your groups dropped as charges increased is a mystery to me. In shooting a ladder its not uncommon to see one incremental charge higher than the last shoot lower. Generally it ladders up. You can see horizontal chains also.

If all your groups steadily dropped it must be something related to shooting cast bullets or changing bore condition.

I'll add again I know nothing of shooting cast bullets or reduced loads. After scrubbing out Gramp's (RIP) 25-20 for a week to rid it of lead I swore I would never touch the stuff:D It works as advertised with jacketed bullets.

Very nice forum software here. Have a good one folks.

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jhrosier posted this 14 September 2008

Joe Brennan wrote: .......

I wish it worked. I think that's why I tried to interpret them so hard.

joe b.

   joe, I have to agree with you, based on my attempt at ladder testing.

I fired many series of tests on separate targets, scanned them into the computer for analysis, and discovered exactly nothing.

The only conclusion that I could reach was that either that particular bullet wasn't ever going to shoot tight groups in my rifle with any load, or ladder testing doesn't work with cast bullets at 100 yards.

I'm considering trying again when my Loverin mould shows up, if it can produce a reasonably tight group to start with.

Jack

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runfiverun posted this 16 September 2008

you are saying it isn't likely that the faster load shoots lower??

you really need to shoot more rifles.

i have seen this come up several times, and have run them through the chrono

i was expecting the opposite results.

and found this through a load that was stringing vertically at 50 yds.

ran it over the chrono had 150 fps velocity variations and was having my wife spot and mark shots for me, she would mark the holes and i would write the velocities down, when we were done i was very surprised.

and of course i had to duplicate the load and shoot it again ,with the same results, is this a gun thing? you bet it is.

do some loads shoot to a different p.o.i. when the bbl heats up?     is it the load or is it the gun?

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Ken Campbell Iowa posted this 16 September 2008

Hi.. when doing various tests such as this, do not forget the effects of ” barrel tuning ” ....  it complicates most tests so much that it is often * the * overriding factor.

........ as you adjust the barrel tuner weight ....  it shifts the groups not only bigger and smaller .... but up, down, sideways, etc.

Just an observation, ken campbell, iowa

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hunterspistol posted this 13 March 2009

  This is basically a question for Jeff.  I just shoot short (10") barrelled Contenders. All the loads I get come from using .1 grain increments. I'm wondering, theory or not, when you use .5 grain increments in a rifle, how do you know when you're close?  All my loads only have about 3/10 grain spread in powder charge, I guess because the pistols are finicky. Using a .5 grain spread would make it easy to completely miss a 'best load' for me. So, what does it look like when you get close?

I want to eventually load for rifle too.

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CB posted this 14 March 2009

Well I look at the group, there will be a point where the group shrinks down and then starts to open back up. I take where the group shrink down and then start fiddling around with .1gr increments. The idea behind the .5 is to get to the general area of the sweet spot quickly without burning up a ton of powder and primers.

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hunterspistol posted this 18 March 2009

Thanks for the answer, that's what I imagined, where the group shrinks in is going to be what you'd look for.

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