Little Help On a Ladder .338LM

[Nefariousd]

I decided to get to work on the Savage 110BA load development today, Had something I've never seen before happen, so I'm not sure how to interpret it. Perhaps someone could advise?

Took four powders in approximately .6% graduations for 10 step rough ladders beginning 5% below Book max (or internet max from Hodgdon)

I cleaned the barrel at each powder switch and fired five sighters/foulers after each cleaning.

Three of the four ladders did just what expected, they spread out vertically between 24 and 46 inches up the face of the target (distance was 650 yards), the nodes showed up and the results were easy to read.

The one that confuses me is one that stayed within 6 inches vertical from high to low with all ten charges. There is a node there but everything stayed VERY close together. it was one of the middle strings and the one after it spread out like I expected as did the one before.

Thoughts?

 

[ChrisGarrett]

Re: Little Help On a Ladder .338LM

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Nefariousd</div><div class="ubbcode-body">I decided to get to work on the Savage 110BA load development today, Had something I've never seen before happen, so I'm not sure how to interpret it. Perhaps someone could advise?

Took four powders in approximately .6% graduations for 10 step rough ladders beginning 5% below Book max (or internet max from Hodgdon)

I cleaned the barrel at each powder switch and fired five sighters/foulers after each cleaning.

Three of the four ladders did just what expected, they spread out vertically between 24 and 46 inches up the face of the target (distance was 650 yards), the nodes showed up and the results were easy to read.

The one that confuses me is one that stayed within 6 inches vertical from high to low with all ten charges. There is a node there but everything stayed VERY close together. it was one of the middle strings and the one after it spread out like I expected as did the one before.

Thoughts?
</div></div>

First of all, 650 yds is about 350 yds too long for precise work ups, so you might want to set the targets up next time, at say 200 yds, or even 300 yds.

These are still easy enough distances to shoot properly, with little worry about enviromentals coming into play, but long enough to get an idea of how the bullets will behavee after they pass the standard 100 yds.

If I could shoot at 300 yds for workups and I'm stuck at 100 yds, I'd load up at least 10 rounds for each powder/bullet weight combo, maybe 3, or perhaps 4 combos total. At the weights found in the 338LM, I might just go coarse and do 1 grain increments.

This would give me 2 groups of 5, for those 3-4 combos and I'd feel good about having a second group incase I mucked the first one up with a flyer.

This will be spendy in the beginning, but I think it will yield better results and workups are a lot of the fun to begin with, anyhow.

As far as your method goes, you have a lot of heat generated by the 338LM and that barrel will be too hot to shoot after only 5-8 rounds, so it could just be heating up for a gain/decrease in velocity, depending on how your tube behaves. This will cause some stringing at 650 yds.

Regarding the 1 combo that didn't string, that could just be you settling into the gun at that moment in time. You don't provide chrono data, so I can't say if it's really a 'velocity' or 'consistency' issue in your reloading procedure.

Long range shooting is much like hitting a golf ball in that you don't have to be off by much to place your ball into the next fairway over.

Set up at 300 and run the tests again, is my advice. Get a chrono and check your SDs and your velocities.

Chris

 

[TimK]

Re: Little Help On a Ladder .338LM

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

First of all, 650 yds is about 350 yds too long for precise work ups, so you might want to set the targets up next time, at say 200 yds, or even 300 yds.



</div></div>

No, no, no.

To the OP, I recently did a ladder on my .308 at 600, and got a total vertical spread of less than 6". I had 4 loads (0.1g increments) that were within 3/4" vertically. I think you found your powder.

 

[Nefariousd]

Re: Little Help On a Ladder .338LM

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

First of all, 650 yds is about 350 yds too long for precise work ups, so you might want to set the targets up next time, at say 200 yds, or even 300 yds.


As far as your method goes, you have a lot of heat generated by the 338LM and that barrel will be too hot to shoot after only 5-8 rounds, so it could just be heating up for a gain/decrease in velocity, depending on how your tube behaves. This will cause some stringing at 650 yds.
</div></div>

Hi Chris,

Thanks for your input. I have to disagree with a few points the above statements.

At 300 Yards the Lapua stacks everything so tight vertically it's hard to read.

My 300wm load was developed between 600-1000 yards and it's quite good. My 308 load was developed in the same fashion using this Article for instruction.



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

Regarding the 1 combo that didn't string, that could just be you settling into the gun at that moment in time. You don't provide chrono data, so I can't say if it's really a 'velocity' or 'consistency' issue in your reloading procedure.

</div></div>

This could be, but I'm not inclined to think it's the case. I have several thousand rounds down range at ranges out to a little over 1700 yards with all manner of rifles up to 50's and I tend to acclimate to rifles pretty quickly. People have me zero their stuff for longer ranges frequently.

I don't think the numbers are relevant, other than an unusually low velocity spread over the ladder, which is sort of implied by the tight vertical,so I didn't post them. I've found that rifles tend like what they like and often the SD's are crazy big and the rifle doesn't care. After doing the whole "getting wrapped up in the data" thing to little avail, I tend to go with what the shooting tells me, in this case it's a little confusing.

I guess A better question is: what characteristic am I seeing from this powder?

Is it possible for a node to be 4.5 grains wide?

Do I need to push up some to get the thing to string out to verify that that is the node?

 

[TimK]

Re: Little Help On a Ladder .338LM

You get the typical stringing because the barrel is moving and the bullet is exiting at various points during the motion, right?

Drastically reduced stringing means one of two things that I can think of, 1) barrel motion is reduced or 2) the bullets are all leaving the barrel at the same point in the range of motion.

I wonder if it might be that barrel motion is reduced with that powder somehow. I don't know enough about internal ballistics to even speculate on a mechanism to explain it, but I wonder if it's tied to burn rate.

On the plus side, what you are really looking for is small vertical spread. Whether you know how or not, you found it. You've got only 1 moa of vertical from min to max charge, and I assume you found a node even smaller. Unless there is some other reason to dislike that powder (temperature sensitivity or something), it sounds like it ought to be extremely insensitive to charge weight. Why not just run with it?

 

[ChrisGarrett]

Re: Little Help On a Ladder .338LM

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Nefariousd</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: ChrisGarrett</div><div class="ubbcode-body">

First of all, 650 yds is about 350 yds too long for precise work ups, so you might want to set the targets up next time, at say 200 yds, or even 300 yds.


As far as your method goes, you have a lot of heat generated by the 338LM and that barrel will be too hot to shoot after only 5-8 rounds, so it could just be heating up for a gain/decrease in velocity, depending on how your tube behaves. This will cause some stringing at 650 yds.
</div></div>

Hi Chris,

Thanks for your input. I have to disagree with a few points the above statements.

At 300 Yards the Lapua stacks everything so tight vertically it's hard to read.

My 300wm load was developed between 600-1000 yards and it's quite good. My 308 load was developed in the same fashion using this Article for instruction.



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

Regarding the 1 combo that didn't string, that could just be you settling into the gun at that moment in time. You don't provide chrono data, so I can't say if it's really a 'velocity' or 'consistency' issue in your reloading procedure.

</div></div>

This could be, but I'm not inclined to think it's the case. I have several thousand rounds down range at ranges out to a little over 1700 yards with all manner of rifles up to 50's and I tend to acclimate to rifles pretty quickly. People have me zero their stuff for longer ranges frequently.

I don't think the numbers are relevant, other than an unusually low velocity spread over the ladder, which is sort of implied by the tight vertical,so I didn't post them. I've found that rifles tend like what they like and often the SD's are crazy big and the rifle doesn't care. After doing the whole "getting wrapped up in the data" thing to little avail, I tend to go with what the shooting tells me, in this case it's a little confusing.

I guess A better question is: what characteristic am I seeing from this powder?

Is it possible for a node to be 4.5 grains wide?

Do I need to push up some to get the thing to string out to verify that that is the node?
</div></div>

Hi, well, we'll just have to agree to disagree on whether it's good practice to work up at 650 yds, vs. 300 yds, or 200 yds, starting from scratch. You didn't mention that you shot these combos at 300 yds and they shot tightly, which might have colored my initial response to you.

This being said, you offer no chrono data, so we don't know what's really up. You do mention that you have vertical stringing from 24" to 46" at 650 yds.

You don't mention how many rounds for each charge weight and powder combo you ended up shooting? You state 10 charges, so is it one round per charge, per powder shot?

24"-46" at 650 yds is a lot of variation. Let's just call it 600 yds for easier math, so that's 4-7.5 MOA. Something's going on and without knowing whether your rounds are shooting at a consistent velocity, I'm just guessing. Obviously, you found a node with one combo, but that wasn't really your question, at least how I understood it to be.

If you use a ballistics program and plug in velocity and BC, you'll probably see that to give vertical spreads in the numbers you give, your velocities would have to be quite disparate.

Maybe you can clarify things, with specifics, like what powders you used, what bullets, brass, primers, seating depth, how many rounds per each increment were shot, stuff like that.

I think that most people here would agree with me, that when at least starting from scratch, 650 yds is a long distance to be doing critical workups. At 300 yds on paper, you'll have a pretty good idea on how they'll perform at 500 yds, 1000 yds, etc.

At 1700 yds, you have enviromentals that will probalby dictate where the bullets land, moreso than the particulars in reloading parameters, assuming that they shot fine at say...that 300 yd distance.

Chris

 

[ChrisGarrett]

Re: Little Help On a Ladder .338LM

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Tim K</div><div class="ubbcode-body">You get the typical stringing because the barrel is moving and the bullet is exiting at various points during the motion, right?

Drastically reduced stringing means one of two things that I can think of, 1) barrel motion is reduced or 2) the bullets are all leaving the barrel at the same point in the range of motion.

I wonder if it might be that barrel motion is reduced with that powder somehow. I don't know enough about internal ballistics to even speculate on a mechanism to explain it, but I wonder if it's tied to burn rate.

On the plus side, what you are really looking for is small vertical spread. Whether you know how or not, you found it. You've got only 1 moa of vertical from min to max charge, and I assume you found a node even smaller. Unless there is some other reason to dislike that powder (temperature sensitivity or something), it sounds like it ought to be extremely insensitive to charge weight. Why not just run with it? </div></div>

Tim, I actually agree with this, but reading the OP's reply to my post, he seems to be a well diciplined shooter, so absent any barrel movement due to breathing, there's probably only one reason why he's getting stringing of 24"-46" at only 650 yds and that's velocity, which WILL cause vertical stringing, but IMO, not that much, unless things are really out of whack--velocity-wise.

I just can't say without seeing velocity numbers and SDs.

Chris

 

[TimK]

Re: Little Help On a Ladder .338LM

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: ChrisGarrett</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Tim K</div><div class="ubbcode-body">You get the typical stringing because the barrel is moving and the bullet is exiting at various points during the motion, right?

Drastically reduced stringing means one of two things that I can think of, 1) barrel motion is reduced or 2) the bullets are all leaving the barrel at the same point in the range of motion.

I wonder if it might be that barrel motion is reduced with that powder somehow. I don't know enough about internal ballistics to even speculate on a mechanism to explain it, but I wonder if it's tied to burn rate.

On the plus side, what you are really looking for is small vertical spread. Whether you know how or not, you found it. You've got only 1 moa of vertical from min to max charge, and I assume you found a node even smaller. Unless there is some other reason to dislike that powder (temperature sensitivity or something), it sounds like it ought to be extremely insensitive to charge weight. Why not just run with it? </div></div>

Tim, I actually agree with this, but reading the OP's reply to my post, he seems to be a well diciplined shooter, so absent any barrel movement due to breathing, there's probably only one reason why he's getting stringing of 24"-46" at only 650 yds and that's velocity, which WILL cause vertical stringing, but IMO, not that much, unless things are really out of whack--velocity-wise.

I just can't say without seeing velocity numbers and SDs.

Chris </div></div>


Chris,

I mean no disrespect, but I'm wondering if you're familiar with the ladder test. Some of your questions lead me to believe you're not. If you haven't already, you might consider reading this . The OP's question and methodology may make more sense to you if you understand what he's doing.

 

[ChrisGarrett]

Re: Little Help On a Ladder .338LM

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Tim K</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: ChrisGarrett</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Tim K</div><div class="ubbcode-body">You get the typical stringing because the barrel is moving and the bullet is exiting at various points during the motion, right?

Drastically reduced stringing means one of two things that I can think of, 1) barrel motion is reduced or 2) the bullets are all leaving the barrel at the same point in the range of motion.

I wonder if it might be that barrel motion is reduced with that powder somehow. I don't know enough about internal ballistics to even speculate on a mechanism to explain it, but I wonder if it's tied to burn rate.

On the plus side, what you are really looking for is small vertical spread. Whether you know how or not, you found it. You've got only 1 moa of vertical from min to max charge, and I assume you found a node even smaller. Unless there is some other reason to dislike that powder (temperature sensitivity or something), it sounds like it ought to be extremely insensitive to charge weight. Why not just run with it? </div></div>

Tim, I actually agree with this, but reading the OP's reply to my post, he seems to be a well diciplined shooter, so absent any barrel movement due to breathing, there's probably only one reason why he's getting stringing of 24"-46" at only 650 yds and that's velocity, which WILL cause vertical stringing, but IMO, not that much, unless things are really out of whack--velocity-wise.

I just can't say without seeing velocity numbers and SDs.

Chris </div></div>


Chris,

I mean no disrespect, but I'm wondering if you're familiar with the ladder test. Some of your questions lead me to believe you're not. If you haven't already, you might consider reading this . The OP's question and methodology may make more sense to you if you understand what he's doing.



</div></div>

Hi, I'm familiar with ladder loading, as well as the OCW method, for load work up and I've been reloading for about sixteen years. I reload for the 338LM and have shot it out past 1000 yds for roughly four and a half years.

At 650 yards, there are enviromentals that 'start' to come into play. Also, as you pointed out, unless you're a world class benchrest shooter, shooting from a stable rest, shooter error gets magnified quite a bit at that range. Not a good thing for load development, IMO.

I just can't say what's up with this fellow's shooting session and need more info, is all.

What questions which I asked, are confusing to you?

Take care, Chris

 

[TimK]

Re: Little Help On a Ladder .338LM

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: ChrisGarrett</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Tim K</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: ChrisGarrett</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Tim K</div><div class="ubbcode-body">You get the typical stringing because the barrel is moving and the bullet is exiting at various points during the motion, right?

Drastically reduced stringing means one of two things that I can think of, 1) barrel motion is reduced or 2) the bullets are all leaving the barrel at the same point in the range of motion.

I wonder if it might be that barrel motion is reduced with that powder somehow. I don't know enough about internal ballistics to even speculate on a mechanism to explain it, but I wonder if it's tied to burn rate.

On the plus side, what you are really looking for is small vertical spread. Whether you know how or not, you found it. You've got only 1 moa of vertical from min to max charge, and I assume you found a node even smaller. Unless there is some other reason to dislike that powder (temperature sensitivity or something), it sounds like it ought to be extremely insensitive to charge weight. Why not just run with it? </div></div>

Tim, I actually agree with this, but reading the OP's reply to my post, he seems to be a well diciplined shooter, so absent any barrel movement due to breathing, there's probably only one reason why he's getting stringing of 24"-46" at only 650 yds and that's velocity, which WILL cause vertical stringing, but IMO, not that much, unless things are really out of whack--velocity-wise.

I just can't say without seeing velocity numbers and SDs.

Chris </div></div>


Chris,

I mean no disrespect, but I'm wondering if you're familiar with the ladder test. Some of your questions lead me to believe you're not. If you haven't already, you might consider reading this . The OP's question and methodology may make more sense to you if you understand what he's doing.



</div></div>

Hi, I'm familiar with ladder loading, as well as the OCW method, for load work up and I've been reloading for about sixteen years. I reload for the 338LM and have shot it out past 1000 yds for roughly four and a half years.

At 650 yards, there are enviromentals that 'start' to come into play. Also, as you pointed out, unless you're a world class benchrest shooter, shooting from a stable rest, shooter error gets magnified quite a bit at that range. Not a good thing for load development, IMO.

I just can't say what's up with this fellow's shooting session and need more info, is all.

What questions which I asked, are confusing to you?

Take care, Chris </div></div>

Chris,

It sounds like you know more than I do and have more experience to boot. The comments that got me off track were the places where you directly contradicted the procedure I linked to. Specifically, the author recommends one shot per charge weight (you asked how many) and he also recommends 600+ yards. Those two things together made me think you weren't familiar with the methodology. My mistake!

I disagree that environmentals come into play at 600y if you're specifically referencing wind. Since we're only looking for vertical dispersion, wind is irrelevant. The whole point of long range is to magnify the issues.

 

[ChrisGarrett]

Re: Little Help On a Ladder .338LM

Tim, you're kind of missing my point, I guess?

One needs to benchmark things first, before going out to any great distance and banging away. Bullets will often be somewhat unstable, or less than true flying, out of the muzzle and then 'go to sleep' so-to-speak and settle down through their remaining time of flight. This is why many loads will shoot fine at 100 yds and not so fine at longer ranges.

The OP didn't mention that these specific combos had already shot great at 300 yds, so as I said, my initial reply would have differed.

Regarding enviromentals having an effect at 650 yds, what about mirage, or barrel mirage? Those are two factors that would certainly come into play vis-a-vis vertical stringing and especially barrel mirage, with all the heat a 338LM generates in only a few rounds down the pipe.

I agree with you, that wind wouldn't be a factor in vertical stringing, but going by the fellow's amount of stringing, there are two glaring reasons I can offer up as to why this is.

One is in agreement with your post above and blaming it on the shooter, ah-la barrel movement up and down (breathing issues?) or the second which is velocity differences. I kind of discount the latter, because, even acknowleging .6gr steps, that's a lot of difference for a .6x10=6gr spread.

Assuming it wasn't shooting error, we have to look at velocities to account for that discrepency and I honestly don't think it's entirely the fault of velocity deviation due to reloading methods.

Could it be that, as I mentioned, the Savage barrel is heating up, thereby expanding the bore and causing inconsistent velocities, leading to that large 4 MOA-7.5 MOA spread?

Inquiring minds want to know, but we can only guess without chrono data to help us out.

Also, regarding the ladder test method, if you're familiar with standard deviation and desired sample size, a sample size of only one round per charge weight and/or powder type, isn't really valid for testing protocol purposes. With all other factors to contend with, it just doesn't tell one much.

Chris

 

[Nefariousd]

Re: Little Help On a Ladder .338LM

Yes, I WANT vertical stringing, it's a ladder.

"Took four powders in approximately .6% graduations for 10 step rough ladders beginning 5% below Book max (or internet max from Hodgdon)"

The whole point is to get vertical stringing to find the node.

This powder didn't string like it should and i found it perplexing.

Unfortunately, the node that appears to be there has the bullets going a little slow for the intended purpose or I'd call it good. I used four powders (I'll probably add more as they become available)

I'm looking for a specific velocity/node combination to accomplish specific objectives.

 

[ChrisGarrett]

Re: Little Help On a Ladder .338LM

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Nefariousd</div><div class="ubbcode-body">Yes, I WANT vertical stringing, it's a ladder.

"Took four powders in approximately .6% graduations for 10 step rough ladders beginning 5% below Book max (or internet max from Hodgdon)"

The whole point is to get vertical stringing to find the node.

This powder didn't string like it should and i found it perplexing.

Unfortunately, the node that appears to be there has the bullets going a little slow for the intended purpose or I'd call it good. I used four powders (I'll probably add more as they become available)

I'm looking for a specific velocity/node combination to accomplish specific objectives.


</div></div>

Thanks for chiming in again.

Did you shoot 1 shot per charge weight, or was it a group of 3 or perhaps 5?

If it was one shot per charge weight, you're really not being told much except that your higher charge weights are yielding higher velocities, as would be expected, leading to flatter flying bullets.

If you were using the OCW method, you'd have taken shots at 10 different bulls, in round robin fashion and fired three shots per group. This would have given you a better idea of your velocity/accuracy node ie: barrel harmonics.

Anyhow, I can't really say why the one batch failed to yield as much stringing, other than to say that perhaps the charge weights weren't all that different, but I wasn't there looking over your sholder while you were loading them up?

Chris

 

[TimK]

Re: Little Help On a Ladder .338LM

Chris,

I still don't think you understand ladder testing. Have you really read the post I linked to?

Nefarious,

I hope someone comes along who can shed some light. Maybe the fact that all the loads in the non-stringing powder are slow holds a clue. Did you see any signs of pressure on the high end of those loads? Maybe you're way below max for some reason. I think you speculated this might be the cause in your OP, and I wonder if you might be right.

 

[ChrisGarrett]

Re: Little Help On a Ladder .338LM

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Tim K</div><div class="ubbcode-body">Chris,

I still don't think you understand ladder testing. Have you really read the post I linked to?

Nefarious,

I hope someone comes along who can shed some light. Maybe the fact that all the loads in the non-stringing powder are slow holds a clue. Did you see any signs of pressure on the high end of those loads? Maybe you're way below max for some reason. I think you speculated this might be the cause in your OP, and I wonder if you might be right.

</div></div>

Tim,

I did read the post and I read all of the subsequent replies in the thread. It seems that most of the people replying are new to this site and I don't know if that means new to shooting longer ranges, or even new to reloading?

There are different 'ladder' type tests one can do and TresMon's method is but one.

Here's a different method for achieving the same thing and many experienced shooters here on the 'hide are using this procedure for finding the 'low velocity' node and finding the 'high velocity' node. Yes, most barrels will have both nodes.

It's the OCW method and you can read about it here:

Dan Newberry's OCW method for finding the accuracy nodes

What method works best for you, is ultimately up to you. My point of contention with the OP is that this shooting of a 10-14 shot string at long distances presupposes the fact that a shooter can be perfectly on target for all of those shots and that can be tough to do for all but the best shooters and even then, those using some sort of Ransom rest or $4,000 gyro-stabalized shooting rest.

I just ran the numbers for a 250gr .338 SMK at 650 yards, in 25 fps increments beginning at 2700 fps and moving up to 2950 fps (11 shots total) and the increase in vertical height is pretty much uniformly at 2" per 25 fps increment (a little taller at the lower velocities and a bit shorter towards the higher end). This is just an FYI, as I was bored, lol.

Anyway, I guess I've beaten my point to death, so it's probably best if I leave it at that.

Have a good one, Chris

 

[Nefariousd]

Re: Little Help On a Ladder .338LM

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Tim K</div><div class="ubbcode-body">Chris,

I still don't think you understand ladder testing. Have you really read the post I linked to?

Nefarious,

I hope someone comes along who can shed some light. Maybe the fact that all the loads in the non-stringing powder are slow holds a clue. Did you see any signs of pressure on the high end of those loads? Maybe you're way below max for some reason. I think you speculated this might be the cause in your OP, and I wonder if you might be right.

</div></div>

Hi Tim, Yes I think you're right about being way below max. I consulted a few other sources and searched a few forums and it seems the max load listed is about 6 grains below what everyone else is saying. It's kind of humorous how inconsistent all of the data charts are, I know this is pretty normal but in this case one of the manuals lists what is just bad information, and Hodgdon's site give the max load with a ridiculously low velocity figure, they couldn't possibly have shot the test load; it must be either a misprint or software extrapolated.

I had no pressure signs so I think I'll shoot the deal again from just below where I left off up to just above the max load gleaned from further research and see what happens..

My target marker is gonna be mad, I had him out in the sun all day Sunday

Chris,

In answer to one question the ladders are shot in groups of three, one up,one down,one up. The strings are shot fast to keep the heat in the gun and the gun is left fouled for each different powder because the idea is to simulate the actual operational conditions it will be used in.

OCW is good; but, I usually use it to confirm the data gathered by the long range ladders, It's a little cumbersome to use a target large enough to hold all ten bulls at distance make sure they're all level etc with the terrain we're using. I'm not sure up close like Dan recommends would work in this instance there seems to be a lot of speculation whether or not the 300 SMK's even fully stabilize before 300-350 and after looking at the oddly shaped holes in some of the close targets I suspect this might be the case. I might give OCW a whack out of curiosity. The end use of the load is for a 1400-1800M fast paced competition we're working up, hence the need for specific velocity/node parity.

 

[TimK]

Re: Little Help On a Ladder .338LM

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: ChrisGarrett</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Tim K</div><div class="ubbcode-body">Chris,

I still don't think you understand ladder testing. Have you really read the post I linked to?

Nefarious,

I hope someone comes along who can shed some light. Maybe the fact that all the loads in the non-stringing powder are slow holds a clue. Did you see any signs of pressure on the high end of those loads? Maybe you're way below max for some reason. I think you speculated this might be the cause in your OP, and I wonder if you might be right.

</div></div>

Tim,

I did read the post and I read all of the subsequent replies in the thread. It seems that most of the people replying are new to this site and I don't know if that means new to shooting longer ranges, or even new to reloading?

There are different 'ladder' type tests one can do and TresMon's method is but one.

Here's a different method for achieving the same thing and many experienced shooters here on the 'hide are using this procedure for finding the 'low velocity' node and finding the 'high velocity' node. Yes, most barrels will have both nodes.

It's the OCW method and you can read about it here:

Dan Newberry's OCW method for finding the accuracy nodes

What method works best for you, is ultimately up to you. My point of contention with the OP is that this shooting of a 10-14 shot string at long distances presupposes the fact that a shooter can be perfectly on target for all of those shots and that can be tough to do for all but the best shooters and even then, those using some sort of Ransom rest or $4,000 gyro-stabalized shooting rest.

I just ran the numbers for a 250gr .338 SMK at 650 yards, in 25 fps increments beginning at 2700 fps and moving up to 2950 fps (11 shots total) and the increase in vertical height is pretty much uniformly at 2" per 25 fps increment (a little taller at the lower velocities and a bit shorter towards the higher end). This is just an FYI, as I was bored, lol.

Anyway, I guess I've beaten my point to death, so it's probably best if I leave it at that.

Have a good one, Chris

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Hey Chris,

I'd not seen that exact link before, but I've read others like it. I understand where you're coming from.

We lost sight of Nefarious's actual question, which was why did three powders give the expected results and one not. It seems he may have found a possible explanation, and I'm looking forward to an update.

Nafarious,

I don't envy you telling your target marker he has to do it again. I'd like to re-run a ladder test I just did a few weeks ago because I now want to switch bullets. I wore out two guys over two different days, and the only person left is my wife. I'm pretty sure I'm sticking with the current projectile.

 

[heavy barrel]

Re: Little Help On a Ladder .338LM

Chris,
I think the barrel movement Tim is referring to is barrel harmonics, not shooter error.. at least that is how I read it.

 

[ChrisGarrett]

Re: Little Help On a Ladder .338LM

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: heavy barrel</div><div class="ubbcode-body">Chris,
I think the barrel movement Tim is referring to is barrel harmonics, not shooter error.. at least that is how I read it. </div></div>

I realize that harmonics are an issue, but as Tim says and which I touched upon in my first or second post, the original question is why did the OP get only 6" of vertical stringing over 10 shots with powder X, when 3 other powders gave between 24" and 46" of stringing?

My thought, without having any chrono data to go by, is that the charges (and hence velocities) weren't all that disparate, in the end.

Remember, as one poster stated in the TresMon Ladder thread, you might just catch the barrel in a downward motion, causing the bullet to deviate downard and not upward. What...50/50% chance?

Let's face it, that barrel isn't moving up and down like a kid on a pogo stick, either. 46" of vertical stringing, by my calculated example above for the 250gr SMK (2700-2950 fps), would only come about over a larger and much faster moving sample size, if shooter error isn't the root cause, or in the least, partially to blame.

Holding a rifle steady on the exact same spot for 3x10 shots (OP added he shot 3 rounds per charge, I think?) at 650 yards isn't an easy task. Especially when the data set one is after, has such as fine resolution.

Chris

 

[Nefariousd]

Re: Little Help On a Ladder .338LM

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

Chris,

Let's face it, that barrel isn't moving up and down like a kid on a pogo stick, either. 46" of vertical stringing, by my calculated example above for the 250gr SMK (2700-2950 fps), would only come about over a larger and much faster moving sample size, if shooter error isn't the root cause, or in the least, partially to blame. </div></div>

True the 46 inches was over a larger size and wider speed range, but the relation ship to velocity and impact point is not nearly as linear as some ballistics programs would have you believe. In that particular set for a slight increase in velocity there were places where a small increase in velocity produced 9 inches of climb, three times in a row. I doubt if by looking at the ballistics readouts you'll find places where 25fps made a 9 inch trajectory change. As you said in your original reply it doesn't take much error to create quite a bit of movement at the target. The only explanation then can be harmonics, a slight change in the angle of departure do to barrel whip created the difference between the software and the actual printing on the target. If you look at Jason Baney's ladder targets in the 6mmbr article they show the same thing, and if you run the numbers on his loads I bet they'll show different than the actual pinting. I'll save some time and put the picture here

3/10th of a grain gives what looks to be a 6inch jump up the target. This can't be velocity alone, harmonics play a much bigger role. The barrel doesn't have to jump up and down like a pogo stick, portions of degrees of change in angle of departure are magnified significantly at distance. Which is why I use distance.

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: ChrisGarrett</div><div class="ubbcode-body">
Holding a rifle steady on the exact same spot for 3x10 shots (OP added he shot 3 rounds per charge, I think?) at 650 yards isn't an easy task. Especially when the data set one is after, has such as fine resolution.

Chris
</div></div>

That is true, in fact, holding the rifle over the exact same spot twice is very difficult (some people, theoretical physicists come to mind) would wager that it's impossible. But things are all relative hence the 3 times up and down. These are rough ladders to see where to start fine tuning. The aiming point I use is a 13-inch by 21-inch diamond made of two inch duct tape on the stand below where the shots for record are recorded. The board is 8 feet tall and 4 feet wide. The rifle sets in a rest with a rear bag. You don't need to hold 1/8 moa to discern trends

 

[heavy barrel]

Re: Little Help On a Ladder .338LM

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: ChrisGarrett</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: heavy barrel</div><div class="ubbcode-body">Chris,
I think the barrel movement Tim is referring to is barrel harmonics, not shooter error.. at least that is how I read it. </div></div>

<span style="font-weight: bold">I realize that harmonics are an issue,</span> but as Tim says and which I touched upon in my first or second post, the original question is why did the OP get only 6" of vertical stringing over 10 shots with powder X, when 3 other powders gave between 24" and 46" of stringing?

My thought, without having any chrono data to go by, is that the charges (and hence velocities) weren't all that disparate, in the end.

Remember, as one poster stated in the TresMon Ladder thread, you might just catch the barrel in a downward motion, causing the bullet to deviate downard and not upward. What...50/50% chance?

Let's face it, that barrel isn't moving up and down like a kid on a pogo stick, either. 46" of vertical stringing, by my calculated example above for the 250gr SMK (2700-2950 fps), would only come about over a larger and much faster moving sample size, if shooter error isn't the root cause, or in the least, partially to blame.

Holding a rifle steady on the exact same spot for 3x10 shots (OP added he shot 3 rounds per charge, I think?) at 650 yards isn't an easy task. Especially when the data set one is after, has such as fine resolution.

Chris



</div></div>

Barrel harmonics is the whole reason for doing a ladder test or the ocw test. You are trying to find the node where the barrel is sitting somewhat still.