38-55 ; Velocity for ladders

[Cast10]

Howdy!

I am preparing to load my first ladders for my new rifle. Winchester 94 Sporter with 24” barrel at 1:15. I’ve poured some Lee 379-250-RF that drop at 249.3 - 251.5.

My question is this: Test data from Lyman uses a 30” test barrel. How much difference have you guys seen between this data and actual rifles with 24” or 20” or whatever length less than the 30”? I’m shooting for around 1500fps.
TIA!

[veeman]

Ladders? What does that mean?

[Cast10]

Ladders? What does that mean?

Example;
22.0 gr of powder
22.3
22.6
22.9
23.2
Etc.

[huntinlever]

Isn't ladder testing where you shoot one round at each load charge, get vertical stringing, and look for nodes along that stringing where two or more charge levels tend to group more than others, hopefully backed up with better chrony stats at those same charges?

(I'm distinguishing that from "standard" load development of multiple shots per charge, looking for better grouping and chrony stats per charge string).

[Snakeoil]

I agree with Cast 10's definition of Ladder Testing. But he was asking for load tips wrt barrel length, not a semantics lesson.

Cast 10, your velocity will be down a bit because the pressure has less time to work on the bullet. But we are not talking huge variations. I shoot .35-55 in a High Wall so I went into GRT and took one of my 2400 loads and modified it to get 1500 fps in a 30 inch bbl with a 250 gr bullet. I then started shortening the barrel and recording the MV. Here are the numbers

Load is 16.7 2400 under 250 cast bullet

1504 - 30"
1485 - 28"
1464 - 26"
1441 - 24"
1387 - 20"

So, about 100 fps nomimal drop between 30" and 20".

I put in a 20" barrel and kept upping the powder until I hit 1500. 18.6g of 2400 will give you 1500.3 fps

Plugged in 24" in for that same load and MV went to 1556.7 fps.

Adjusted the powder to get 1500 out of a 24" bbl and 17.7g gave 1502.3 fps.

Hope this helps.

regards,
Rob

[huntinlever]

Rob, not trying to give a semantics lesson, just not wanting him (or veeman, who asked what "ladder" means) to go into a load development wasting components if he had another idea in mind. I'm not all that knowledgeable, which is why I posed it as a question and not a statement. I know I can get confused, anyway.

In case there is still a question, just a quick search, Ladder Testing:

Ladder Test Defined
What is a ladder test? A ladder test is, fundamentally, a method of testing a load combination using continuous increments while looking for a cluster of consecutive shots showing similar points of impact (POI). Usually the powder charge is adjusted incrementally while noting/tracking the point of impact variations in the vertical plane, and looking for plateaus on the target. The idea being that your best load will appear where several sequential, incremental charges impact in nearly the same place on the target. Basically you are trying to visualize a "sweet-spot" in the barrel harmonics by using the bullet's impact on a target.

https://www.6mmbr.com/laddertest.htm...mpact%20(POI).

.

Anyway, not trying to muddy the waters. Thanks for an interesting question, OP.

[M-Tecs]

Some good discussion here on incremental verse ladder testing.

https://castboolits.gunloads.com/sho...57#post5382457

Here we have another example, causing confusion, of inappropriate terminology either nonintentional or otherwise. We see this often on this forum with terms which are apparently made up or of some local use which are not used in firearm or ballistic usage. For example; the term “bullet” is oft verbalized as “head”, “pill”, “tip” and [not intending to stab a sacred cow] “boolet”. We can generally surmise what is intended by the rest of the post. However, sometimes not.

So, what does the OP mean by “ladder testing”?

Would seem that ryanmattes thinks the OP is referring to “incremental” testing. ILostMyGoat, the OP, seems to concur and admits “ladder testing” may have been a poor choice of words.M-Tecs and Bigslug are discussing the Audette Ladder Test as correctly done. ABJ, apparently is using the term “ladder test” for what he is really doing is an “incremental test”.
Which is it, an incremental test, or a ladder test?

Is there a difference between the two?

Yes, there is a distinct difference between the two.

An incremental test is to load a cartridge with incrementally increasing weights [may be .2, .3, .5 or even 1.0 gr increments depending on the cartridge volume and burn rate of the powder used] from a “start” load to a “maximum” load. That’s the old way, tried and true. It used to be, and still is by many, called the Incremental Load Development Method or ILDM for short. The problem with the misuse of the term “ladder test” is when it is applied to this method of load testing.
Unfortunately, that term (IDLM) is also used for the Creighton Audette Ladder Test, ALT for short. Audette’s article describing his Ladder Test method and why and when it should be used was first published in the 1997 Precision Shooting Annual. It may have also been published in a gun magazine earlier. There also is an excellent discussion and description by Randolph Constantine which I also believe was published in the Precision Shooting Annual.

Audette was a long range match shooter as was Constantine. They used precision rifles with match load components capable of sub moa accuracy. The minimum Audette recommended for testing using his “Ladder” method was 300 yards. He did most of his testing at 600 and 1000 yards. It should be noted that Audette, when developing his “ladder” test method was loading his 300 magnum cartridge using an electronic measuring scale. The machine measured charges using IMR 4350 were up to 1.5 gr variation (if I remember correctly). Audette tested to see if there was a load with a +/- 1.5 gr variation would “group” with sufficient accuracy for match shooting at known range long distances. His testing for that resulted in his “Ladder Test” method.
Audette’s “Ladder Test” method was never intended to be a method for initial load development at shorter ranges. It was developed to perfect a load for match shooting at a specific long ranges. The problem with load testing at shorter ranges of 50 or 100 yards or even 200 yards is there is no way to know the cone of fire (area of shot distribution of the group size) with loads of unproven ability. Audette and Constantine used know loads with match bullets in very accurate rifles. Even then they knew a “ladder test” at such short ranges would be difficult if not impossible to interpret.

Thus, what most who use incremental charge increases from a start load to a maximum load should be calling that method is an “incremental load development method” ILDM] test. They should not be calling it a “ladder test” because it is not. Using the appropriate terminology would help avoid unnecessary confusion.

BTW; Those who are attempting to use an Audette Ladder Test [ALT] to “develop” a load are chasing their tail. I know as I’ve chased my own tail on that one numerous times. I no longer do.

[huntinlever]

Some good discussion here on incremental verse ladder testing.

https://castboolits.gunloads.com/sho...57#post5382457

Awesome, thanks, never seen such a clear post on the distinction.

[Snakeoil]

Paul, I was being a bit tongue-in-cheek and hence my wink icon. But in hindsight, that comment really made no contribution, so would have been better if I had just not made it.

I read the Berger article. It's a good one for others to read on the subject. But I have to admit, that the "1-3 rounds" comment was a first for me. A ladder test has always been at least 3 rounds. Keep in mind that this is a cast bullet discussion, and the variability of the bullet is greater than with jacketed precision bullets like Berger's. So, for me, 3 is a bare minimum. And I'm testing at 100 yds before I move out to 200 to 500.

The article is testing at 500 yds. If you shot 1 round per load at 500 yds with a cast bullet, I'm not sure you'd get the same results. You would also need a day with perfect light and no mirage as vertical placement could be affected by mirage as well as any vertical winds for ranges where you shoot over closer berms. Those Bergers are going a lot faster than our cast slugs and I can see one bullet telling you more.

We could probably discuss the merits of which way is better all day. And I am always open to new and better ways. But I with respect to cast bullets, I have always known a ladder test to be rungs at various charge increments looking for the best group size. Then, repeating the ladder with incremental seating depth (if I'm not breech seating), again looking for the best group size. I normally shoot a minimum of 5 shots per rung and lately have been shooting 10 shots to see what might change as the barrel heats up.

Others may not agree, but with cast bullets, I don't see 1 shot per charge telling you much. Maybe you will find a sweet spot but I don't think you will ever know until you put a least 3 rounds for each charge on paper.

UPDATE: As I was pounding on my keyboard for the reply above, M-Tecs posted that explanation of Ladder vs ILDM. I suspect I am also a victim of the common use of the term "Ladder Test" to mean an ILDM test. So, not one to accept an alternate answer without back up info, I did some digging on the web and found this excellent article on the subject. And even this article tends to give the impression that the terms are used interchangeably, at least in the beginning. What I like about this article is the graphic representation of what the actual ladder test can (not necessarily will) tell you. Keep in mind that the first charts are for velocities and not vertical placement. Again, here is another area where cast bullets may not lend themselves to 1 bullet telling the story.

https://precisionrifleblog.com/2012/...adder-testing/

In my load testing, which are reduced loads in some cases (like .30-06), I find that the Extreme Spread and Std. Dev numbers reflect less than desirable results, yet the group sizes on the target tell a different story, often much better. So, if I were to put 1 round per load over the chrono, I'm not sure it would tell me much. Just last Wed, I tested a bunch of loads and the MV numbers on average were different, but they often overlapped. Not saying that is bad. What I'm saying is that with reduced loads, your Ladder test may tell you more if you use an average MV for a group of shots. And that's why I think a min of 3 rounds per load is necessary as it is also a type of average. I have all the data for the last few test sessions at the range. I may just plot them to see if a flat spot appears, using average MV.

[huntinlever]

Paul, I was being a bit tongue-in-cheek and hence my wink icon. But in hindsight, that comment really made no contribution, so would have been better if I had just not made it.

I read the Berger article. It's a good one for others to read on the subject. But I have to admit, that the "1-3 rounds" comment was a first for me. A ladder test has always been at least 3 rounds. Keep in mind that this is a cast bullet discussion, and the variability of the bullet is greater than with jacketed precision bullets like Berger's. So, for me, 3 is a bare minimum. And I'm testing at 100 yds before I move out to 200 to 500.

The article is testing at 500 yds. If you shot 1 round per load at 500 yds with a cast bullet, I'm not sure you'd get the same results. You would also need a day with perfect light and no mirage as vertical placement could be affected by mirage as well as any vertical winds for ranges where you shoot over closer berms. Those Bergers are going a lot faster than our cast slugs and I can see one bullet telling you more.

We could probably discuss the merits of which way is better all day. And I am always open to new and better ways. But I with respect to cast bullets, I have always known a ladder test to be rungs at various charge increments looking for the best group size. Then, repeating the ladder with incremental seating depth (if I'm not breech seating), again looking for the best group size. I normally shoot a minimum of 5 shots per rung and lately have been shooting 10 shots to see what might change as the barrel heats up.

Others may not agree, but with cast bullets, I don't see 1 shot per charge telling you much. Maybe you will find a sweet spot but I don't think you will ever know until you put a least 3 rounds for each charge on paper.

Lol, I saw some kind of face-palm thingy Didn't take it personally, just wanted to clarify in case someone was confused over the terminology (as much for me as others. I thought M-Tec's and Larry's comments cleared it up well).

Really helpful on the cast bullets, thanks. I'd tried on my 45-70 but realize now that's likely a pointless exercise. I also learned the futile attempt at shorter distances. When I tried it with one shot each, at 100 yards, I had so many so close together it became impossible to distinguish not only any "nodes," but individual shots. I'm also solely looking for good kills at whatever range on whatever animal I'm after, so now I know to leave the "ladder test" to the long range bench rest guys.

[Snakeoil]

"I had so many so close together it became impossible to distinguish not only any "nodes," but individual shots. I'm also solely looking for good kills at whatever range on whatever animal I'm after, so now I know to leave the "ladder test" to the long range bench rest guys."

You and I are opposites. All my cast bullet shooting is in matches. I stopped hunting years ago. Guess I got soft-hearted when the gray hair started to appear.

My goal is to get as close to a tack driver as possible with cast bullets out to 500 yds. My current project is a .32-40 Highwall. Somebody "freshened" the barrel at some point in its long life so the groove diameter is now .326. Took some doing but have it shooting well breech seating. Using iron sights so at a disadvantage from a consistency POV. Waiting for scope blocks from Steve Earle so I can put a Unertl on the rifle. Been shooting a bullet from a borrowed Lee mold that I machined the GC out of 2 years ago for the owner. Drops a bullet at .326 in 30:1. Mold is a PITA to cast with, but the bullet shoots great. But when I finally buy a mold, I suspect it will be a version of the Saeco 632 tapered bullet as it is a known good shooter in this caliber. Schuetzen guys tend to use it.

[huntinlever]

"I had so many so close together it became impossible to distinguish not only any "nodes," but individual shots. I'm also solely looking for good kills at whatever range on whatever animal I'm after, so now I know to leave the "ladder test" to the long range bench rest guys."

You and I are opposites. All my cast bullet shooting is in matches. I stopped hunting years ago. Guess I got soft-hearted when the gray hair started to appear.

My goal is to get as close to a tack driver as possible with cast bullets out to 500 yds. My current project is a .32-40 Highwall. Somebody "freshened" the barrel at some point in its long life so the groove diameter is now .326. Took some doing but have it shooting well breech seating. Using iron sights so at a disadvantage from a consistency POV. Waiting for scope blocks from Steve Earle so I can put a Unertl on the rifle. Been shooting a bullet from a borrowed Lee mold that I machined the GC out of 2 years ago for the owner. Drops a bullet at .326 in 30:1. Mold is a PITA to cast with, but the bullet shoots great. But when I finally buy a mold, I suspect it will be a version of the Saeco 632 tapered bullet as it is a known good shooter in this caliber. Schuetzen guys tend to use it.

! Respects. As much as I'd love to go to an aperture as I hate scoping the gg, I'm pretty much resigned with these old eyes. And that's 100 yards, not 500!

My aim in getting the .338 WM was to round out my home hunting arsenal to cover any distances and terrain not covered with the gg. I hope to do a lot more western hunting as I miss the region's wildernesses. That said, if things (including a forgiving wife) conspire, I do hope to get a single-shot 45-70, some flavor, to throw the truly big boys at longer ranges, just for the pleasure. Maybe then I could tap you.

[Cast10]

Thanks all! I am 45+years reloading and have always loaded 5 rounds on a ‘increment’ to find best grouping. I also shoot over a chrony and watch SD numbers. The 5 shot string method, I have never done. Not that I don’t agree with it, but money ‘wasted’ on 25 rounds or so to arrive at the best is within my wheelhouse.

@Snakeoil - EXCELLENT REPLY and I thank you. I’m working with IMR 4895 (cause I have it on hand) and a Lee 250gr.

[Snakeoil]

First, Cast 10, I'll run that powder on GRT and post the results here. Stay tuned.

Not to hijack this thread, but since the question has been answered, I thought I'd beat the ladder test for cast bullets a bit more.

I took the data for the testing last week and put it into Excel. I ran the average POI for each charge. To make it easy, I drew a horizontal line thru the bullseye and measured ever shot from that line. So a shot thru the X or anywhere on that horizontal line would be zero. Above would be a positive number and below a negative number. Then took the average for the total number of shots.

I plotted the results on a graph. Looking at that chart, I saw what might be considered a flat area so I decided to then plot the group sizes for each charge weight and compare the two charts. Here are the results.



I hope you can read the charts. The data behind them is above the charts.

What I see is what might be considered a flat area/grouping of shot placements that goes from 13.7 to 14.0 charge weight. One could argue that 13.7 does not belong in that grouping. I then looked at the group sizes and the smallest of the bunch is at 13.8.

So, if the ladder theory holds up with cast bullets, and my using the average shot placement for the total group rather than a single shot placement to look for flat spots on a graph of all charge weights shot, then that indicates that the 13.8 to 14.0 charge range is the "sweet spot". Because I used 0.1gr increments, my group size helped me narrow down that range to the best load.

Now, normally, I would never have looked at a comparison of shot placement for all the groups to see if any were aligned horizontally. But in doing so, it confirmed that the 13.8 gr charge weight is the right one for this bullet, rifle when breech seating.

Learned something new today and am grateful. I'm thinking I might plot the average MVs for these same loads to see if a flat spot on the graph shows up. I do remember that the ES and SD decreased with increasing charge weight. I'll post the chart if I do this.

UPDATE: Why wait. The chrono info is in my phone so only took a minute to put into Excel and create another chart. Here is an updated set of charts with Average Muzzle Velocity added. Note that the a similar flat spot can be seen in the MV chart. Just another indication that 13.8 is the right charge for this rifle.

[M-Tecs]

The question I have is how repeatable is the 1 1/4" group at 13.8 grains? A tenth of a gain up or down more than doubles the group size?

[Snakeoil]

The question I have is how repeatable is the 1 1/4" group at 13.8 grains? A tenth of a gain up or down more than doubles the group size?

My mistake for not clarifying that all these groups were shot with iron sights. Lyman 103 rear and a 17A front. So, there is the issue of variability just because of the sights. How much? Hard to say.

If you were looking at the targets, they tell more than the data. A larger group may be caused by one flyer and that could be due to any number of reasons, one of which is old eyes and iron sights. When I was shooting 10 shot groups, I noted any clusters as part of the feedback for the load. For example, on a previous outing shooting 10 shot groups, I put 6 into a 7/8" group and the remaining 4 made the overall group 2-1/4".

I realize that until I put a scope on the rifle, the unknown variability created with iron sights can be misleading. I am waiting for blocks from Steve Earle. When they arrive, I'll put my 20X Unertl on the rifle and repeat some of these tests to confirm/disprove the initial findings and to see if the variability was me or something else.

[Cast10]

First, Cast 10, I'll run that powder on GRT and post the results here. Stay tuned.

Not to hijack this thread, but since the question has been answered, I thought I'd beat the ladder test for cast bullets a bit more.

I took the data for the testing last week and put it into Excel. I ran the average POI for each charge. To make it easy, I drew a horizontal line thru the bullseye and measured ever shot from that line. So a shot thru the X or anywhere on that horizontal line would be zero. Above would be a positive number and below a negative number. Then took the average for the total number of shots.

I plotted the results on a graph. Looking at that chart, I saw what might be considered a flat area so I decided to then plot the group sizes for each charge weight and compare the two charts. Here are the results.



I hope you can read the charts. The data behind them is above the charts.

What I see is what might be considered a flat area/grouping of shot placements that goes from 13.7 to 14.0 charge weight. One could argue that 13.7 does not belong in that grouping. I then looked at the group sizes and the smallest of the bunch is at 13.8.

So, if the ladder theory holds up with cast bullets, and my using the average shot placement for the total group rather than a single shot placement to look for flat spots on a graph of all charge weights shot, then that indicates that the 13.8 to 14.0 charge range is the "sweet spot". Because I used 0.1gr increments, my group size helped me narrow down that range to the best load.

Now, normally, I would never have looked at a comparison of shot placement for all the groups to see if any were aligned horizontally. But in doing so, it confirmed that the 13.8 gr charge weight is the right one for this bullet, rifle when breech seating.

Learned something new today and am grateful. I'm thinking I might plot the average MVs for these same loads to see if a flat spot on the graph shows up. I do remember that the ES and SD decreased with increasing charge weight. I'll post the chart if I do this.

UPDATE: Why wait. The chrono info is in my phone so only took a minute to put into Excel and create another chart. Here is an updated set of charts with Average Muzzle Velocity added. Note that the a similar flat spot can be seen in the MV chart. Just another indication that 13.8 is the right charge for this rifle.

Good info, again! Thank you sir.

[Snakeoil]

Thanks all! I am 45+years reloading and have always loaded 5 rounds on a ‘increment’ to find best grouping. I also shoot over a chrony and watch SD numbers. The 5 shot string method, I have never done. Not that I don’t agree with it, but money ‘wasted’ on 25 rounds or so to arrive at the best is within my wheelhouse.

@Snakeoil - EXCELLENT REPLY and I thank you. I’m working with IMR 4895 (cause I have it on hand) and a Lee 250gr.

Using IMR 4895 and Lee 250gr bullet

31.2 gr in 20" bbl = 1499 fps. Same load in a 24" bbl jumps up to 1570 fps. In a 30" bbl 1654 fps.

29.8 gr in a 24" bbl = 1500 fps. Same load in a 30" bbl is 1583 fps. In a 20" bbl 1429 fps

[Cast10]

Using IMR 4895 and Lee 250gr bullet

31.2 gr in 20" bbl = 1499 fps. Same load in a 24" bbl jumps up to 1570 fps. In a 30" bbl 1654 fps.

29.8 gr in a 24" bbl = 1500 fps. Same load in a 30" bbl is 1583 fps. In a 20" bbl 1429 fps

Wow!
So where does GRT get the info? The Lyman #4 load for a 249gr. is lower, at the mid 1300’s for 29.8 with a 30” test bbl. More of my confusion….

[Snakeoil]

I've only been using GRT for a few months now. My understanding is that the creator (who passed a year ago) was a thermodynamics expert. He wrote the software. He got powder information from various sources, including the powder makers themselves. He assembled quite a team to help him with the program.

I also have found that the GRT predictions are off compared to my chrono readings. I found ways to fudge the GRT input numbers to line up with the chrono numbers to help with future load development for a given caliber.

For me, GRT is a starting point. It also helps me understand what is going on in the chamber. When making reduced loads using pistol powders in rifle cases, it is easy to exceed max pressures. GRT keeps one from doing that. I posted a screen print from GRT in another thread here for someone having trouble with 4227 in a 7mag case. The pressure curve it generated for the load and bullet he was using was like nothing I'd ever seen before. There was no pressure peak. The pressure rose slowly and steadily until the bullet exited the muzzle. It told me that 4227 was not the powder for that application. But it appears the OP either did not know what he was looking at or simply dismissed it as no comment was ever made and the conversation continued on. Could be that because I'm a newbie here that my posts get zero attention from those who have a billion posts under their belt.