Interpreting a Ladder Test

Today I completed two ladder tests as below.

However I'm struggling to interpret the results.

Rifle was my trusty 308 Brno ZKK601.

What do you guys think of these results?

Where to now to develop this further?

Targets were set @ 100m and each larger square (i.e. orange square) on the target is 1"

1st load
10 Rounds of Hornady 150gr spire point, Federal primers, W748 Powder 46.2 grs to 48.0grs in 0.2gr increments
Attachment 22277

2nd load
10 Rounds of Hornady 150gr SST, Federal primers, W748 Powder 46.2 grs to 48.0grs in 0.2gr increments
N.B. pretty sure I pulled the 46.8 round on this test.
Attachment 22279

Any help would be appreciated

Cheers
Pete

Im no expert but i would load up 6 or 9 of 47 and 47.5gr with the sst and see how it groups and play with seating depth from there.
That many shots on paper if accuracy potential is not great gets confusing.

Here is a 9 shot ladder from the barrel i cut into 3 recently.

Attachment 22280

VC
Thanks for this.

Yes I also thought around 47.2 to 47.4grs had merit for the SST load, however it also looks like 46.2 to 46.6grs also looked quite good.

For the spire point load I though 47.2grs to 47.6grs looked good.

I want load up five rounds of each promising load and go back to the range tomorrow to test.

Cheers
Pete

3" is rather big though it is min of deer.

I can give you my .308 load though each rifles different so it may shoot like shit in yours

48.5 or 48 of win 748 shoot around 1/2-1" in ours using fed mag primers

Quote:

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Originally Posted by Toby

3" is rather big though it is min of deer.

I can give you my .308 load though each rifles different so it may shoot like shit in yours

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Toby

Thanks for your suggestion and help.

Yep minute of deer is what this load is for. these ten shot groups measure around 2.5" x 3" which will kill deer all day long, but we can do way better.

This rifle will shoot 165gr ballistic tips into 1" with 45.5grs of W748, even with a blind old shaky bugger like me yanking on the trigger.

I'm sure I can develop a 150gr load that will equal or better this performance as an alternative to the 165gr load.

And as you can see the potential is there just need a bit of guidance in which direction to take so I don't waste too much time chasing down the best loading.

Cheers
Pete

oh yeah 150 Seirra pro hunters

Quote:

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Originally Posted by Toby

oh yeah 150 Seirra pro hunters

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Haven't tried them Toby.

What's your opinion on them?

My 165gr load drops them where they stand.

Not sure why I need another load really but there you go.

Have a reloader....... will use it :thumbsup:

Cheers
Pete

Yeah I like them, killed all the deer and goats me and my brother have pointed them at. Shoot under an inch at 100m so I can't complain

Quote:

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Originally Posted by Toby

Yeah I like them, killed all the deer and goats me and my brother have pointed them at. Shoot under an inch at 100m so I can't complain

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How much do they cost?

Cheers
Pete

I can't actually remember but think they were 60-70 for 100. I have a gut feeling they were 65

Could also try 2208

Quote:

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Originally Posted by veitnamcam

Could also try 2208

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Yep.

Except I love using W748and kinda want to keep the powder choices in the cupboard to a minimum. :)

Cheers
Pete

$61 @ outdoors supplies

Quote:

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Originally Posted by Toby

$61 @ outdoors supplies

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150gr SST's were $65 per 100 and the 165gr SST's were $68 per 100

165gr Nosler Ballistic Tips are around that price for 50 :oh noes:

Cheers
Pete

Nosler are expensive. Only thing that put me off for my new 6.5

Interlocks are cheap and you can get them closer to the lands than sst in mag fit.

Quote:

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Originally Posted by Toby

Nosler are expensive. Only thing that put me off for my new 6.5

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Your not wrong Toby

I like them but being a confirmed Tight Arse doesn't sit well with me when I can got to the Hornady range for half the price.

Cheers
Pete

I have Wile staying in my hut, he is a wealth of reloading knowledge, I will ask him a good 308 150 grain load , I think he is shooting 125 and 130 grain in his 308

Id be loading both at 47.4 and doing groups then playing with seating depth if needed

Sent from my GT-I9300 using Tapatalk

I looked over these results last night and tried to interpret them as best I could and then decided on the following

Hornady 150gr Spire points best grouping was around 47.5grs

Hornady 150gr SSTs best groupings were around 46.5gr and 47.4gr

So I loaded up 5 of each of these and went back to the rage today with the following results.
Attachment 22317Attachment 22318

The end result is 47.5grs of W748 with the 150gr spire points and 47.4grs of W748 with the 150gr SST's is looking good.

Might end up settling on 47.5grs W748 for both projectiles and adjust the seating depth to see if I can close the groups down even more.

Cheers
Pete

I tried to do a ladder test working up a load for my 223 had 10 bullets of different powder weights all go into less than a 2" group at 100m lol. I threw the target away and just did it the normal way, as my test suggested anywhere between 25 and 26.5gr of powder would do.

I think ladder tests are meant to be done at longer ranges, that way you aren't looking at half a millimetre difference, and results should be a bit more obvious.

Quote:

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Originally Posted by Beetroot

I tried to do a ladder test working up a load for my 223 had 10 bullets of different powder weights all go into less than a 2" group at 100m lol. I threw the target away and just did it the normal way, as my test suggested anywhere between 25 and 26.5gr of powder would do.

I think ladder tests are meant to be done at longer ranges, that way you aren't looking at half a millimetre difference, and results should be a bit more obvious.

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Beetroot

That's kinda what happened here.

I'll try those loads at 200m in a week or so and see if I can repeat this result.

Cheers
Pete

P38 I'm a bit lost here on the ladder test thing, what are you looking for? The only time I do a single shot test is to check for pressure, I don't care where they shoot on paper, when I shoot 3 or more of the same load I still don't care where they shoot relevant to the point of aim but how close they are together.
I'm obviously living in the stone age and need some education about this ladder test thing. As I said to Brian a few days ago in a perfect world every shot should rise a1/4 of an inch per 1/2 grain of powder in a direct vertical plane.

Cheers

looking for accuracy nodes within a small powder variance, e.g 30.2 30.4 and 30.0 might all be close meaning that is the accuracy node, can do the same by keeping the sme powder charge and changing seating depths ect.

IMO a waste of time doing it unless its done at 200m+ an with a rifle/shooter combo that is pretty bloody accurate allowing you to interpret results.

Quote:

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Originally Posted by PerazziSC3

looking for accuracy nodes within a small powder variance, e.g 30.2 30.4 and 30.0 might all be close meaning that is the accuracy node, can do the same by keeping the sme powder charge and changing seating depths ect.

IMO a waste of time doing it unless its done at 200m+ an with a rifle/shooter combo that is pretty bloody accurate allowing you to interpret results.

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I think 300m is the typical distance for these tests, definitely not 100m.
The wind usually doesn't matter either as it's really the vertical spreads/nodes you look for.

Just to muddy things further what about doing it this way

OCW Overview - Dan Newberry's OCW Load Development System

Quote:

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Originally Posted by mikee

Just to muddy things further what about doing it this way

OCW Overview - Dan Newberry's OCW Load Development System

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Very interesting Mikee.

Thanks for this.

I do seem to remember reading this quite some time ago but had forgotten all about it.

It would be interesting to complete an OCW on my rifle with these 150gr projectiles and see if we arrive at the same conclusion as I already have.

Cheers
Pete

Quote:

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Originally Posted by P38

Very interesting Mikee.

Thanks for this.

I do seem to remember reading this quite some time ago but had forgotten all about it.

It would be interesting to complete an OCW on my rifle with these 150gr projectiles and see if we arrive at the same conclusion as I already have.

Cheers
Pete

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I would be interested in your results too. I would be worried about getting a shot "out of sequence" but it sounds logical

Using the ladder test at 100m or 200m is hard to interpret there is not enough distance between shots, I use a variation of the OCW I had problems with the round robin system (short attention span) The way I do it is to load powder in increments of .3grains and shoot groups of 3 at 5 targets at 100m and compare the results as Dan Newberry describes, start load is a least 2.0 grains under factory max
and bullets seated to manufacturers specification in the case of .308 at 2.800" usually can get an acceptable load first time, if the pressure sign are ok keep increasing the powder charge until you reach max, It helps if a good brenchrest set up is available then you can repeat the test at 200m with the best loads, if you want to see how good your rifle shoots buy a box of Federal Gold Match 168gr
it is the standard load used by most US Police snipers and Remington test their Match rifles with it, a good way to set a benchmark for you reloads, a load I find shoots well in most .308's is 43.6grs of 2206H and a 150gr Hornady Spire point, it's quite mid and very accurate. Robert.

Attachment 22584

Hi P38. To make it easier for me I numbered your shots. Statistically there are no patterns here, just data that says that ladder testing will not give you the information you are wanting.
Both ladder testing and the OCW method are intended to identify barrel vibration "nodes" as a means to reducing the effect of shot-to-shot variance in a given ammunition. My interpretation of this target is that other factors in your set-up are setting the overall group size, masking the information that the ladder test may otherwise provide. They will do the same thing for OCW testing.
My best advice if you are wanting to shoot smaller groups is to pass on ladder & OCW testing and shoot test groups with each type of bullet that are acceptable for the task you have in mind and hope that one or more of these meets your expectations, sticking with a moderate load for each, 7-shot minimum groups to get a bit of statistical significance. Good luck.

Quote:

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Originally Posted by Puffin

Attachment 22584

Hi P38. To make it easier for me I numbered your shots. Statistically there are no patterns here, just data that says that ladder testing will not give you the information you are wanting.
Both ladder testing and the OCW method are intended to identify barrel vibration "nodes" as a means to reducing the effect of shot-to-shot variance in a given ammunition. My interpretation of this target is that other factors in your set-up are setting the overall group size, masking the information that the ladder test may otherwise provide. They will do the same thing for OCW testing.
My best advice if you are wanting to shoot smaller groups is to pass on ladder & OCW testing and shoot test groups with each type of bullet that are acceptable for the task you have in mind and hope that one or more of these meets your expectations, sticking with a moderate load for each, 7-shot minimum groups to get a bit of statistical significance. Good luck.

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Puffin

Thanks for this. :thumbsup:

I agree the ladder test really didn't tell me anything at the end of the day and the OCW may be too much at this stage.

However I like the look of the two loads I shot groups with the following day.

I'm using this load for hunting at moderate ranges, up to 300m.

I have access to a 200m range and will retest these loads in a week or two shooting some groups.

Cheers
Pete

I was trying a new powder for my .280 and every load from 53.5 to 58 shot into a 2" group the next 2 at 58.5 and 59 moved away appreciably, so I'm going to load 3 at 57, 57.5 and 58 and hopefully get good speed and a smaller group.

Two good things about 3-shot groups; they are cheap, and you're 30-40% through shooting a meaningful number of shots to draw some valid conclusions. Either or both of the 47.5gr loads may shoot very well as you say, and if it was my rifle and load development my next step would be to make those test groups you have planned 10-shot groups of each (same number as used in the ladder test) to confirm this and to see if one of these shows through. If you do please post and let us know.

Three-shot groups are popular. I know this. I don't mean to appear to be down on your efforts either. From personal experience drawing incorrect conclusions (not helped by insufficient data overlayed with some wishful thinking ) is a path to wasting a lot of time and ammunition further down the path of load development, something to be avoided.

Pick three of the shots at random from your 10-shot ladder test. Repeated sampling like that will show up a fair % of these samples as small groups. It says something about what sample size may be required to give an insight into the true "population" doesn't it ?

Some good points raised above. I would be testing the good grouping loads from 100yd at the intended range of use on paper from a solid rest.

Ladder test is well explained here;

6mmbr.com

Today I tested what I considered the most promising load.

I have settled on 47.5grs of W748 at this stage. Testing out three different 150gr projectiles, Horandy SST, Hornady Spire Point & Privi Partisan Spire Point.

I loaded up 5 rounds of each and shot 3 shot groups at 200m with the following results.

Each of the groups look ok to me but I can't explain the POI change as yet except for each was a different type of projectile.

I'm confident I can take any of these hunting but would like to see how much better I can get them.
I was using a 300m sight in target and each square on the grid is 35mm (nearly 1'1/2)

Attachment 22845Attachment 22846Attachment 22847

Cheers
Pete

Pete, what I was angling at previously is that a 10-shot group with one of these projectiles and at one powder charge - say 47.5gr - would likely look something much like your ladder group - I don't think it would be that much smaller just because the charge was fixed. That is representative I believe of the current rifle/shooter/set-up combination. I'm drawing this conclusion because the ladder pattern with what were small changes in powder charge has the appearance of being completely random. The more recent groups at 200m also look (within the limitations of 3-shot groups) to be representative of this level of precision. Different bullets will have different profiles, materials, tolerances etc. so the POI movement with bullet type doesn't seem unexpected, I'm not sure I'd be concerned about that. My assessment is that the rifle/shooter/ammo/set-up is currently 2-3 moa capable, and this may be fine for what you want it to do. If not, then begins the tricky path to finding the contributions that are setting the precision, ideally from the most significant, fixing or improving, and work down the list. I would be inclined to put exact powder charge down the list though. Just my opinion of course. If you plan to stick with your current barrel ( a new True-flite UM fixes many things! ) then continuing to try some other bullets and powders may bring results? Is the barrel copper fouled? If all else fails do much lighter loads shoot better? They often do in my rifles - I'm picking because recoil is an excellent destroyer of consistency in shooting!