Very happy so far, “10 round” load development results.

[Link]

Any signs of pressure ?

 

[Sraw]

Any change that could result in a different powder burn rate (i.e. new Lot of powder or change in primers), case volume (i.e. a new Lot of brass, or different brand of brass), or variance in bullet dimensions (i.e. new Lot of bullets), necessitates at the very minimum enough testing to determine whether the load is shooting the same as it was before the change was made.

The problem with load development procedures that use a very small number of total rounds is that almost by definition, you're testing fairly wide increments in order to cover a sufficiently wide range. Without further fine increment testing, you'll never really know where in the "window" a coarse increment load actually is. Is it right in the middle of the window? Is it right on the very edge? Obviously the latter case will be more prone to going out of tune as conditions change.

There are a variety of charge weight tests including ladders, OCW, etc. Although there are subtle differences in the testing methods, they are essentially all looking at elevation in response to varying charge weight. Both can work. BR shooters tend to favor the ladder approach. F-Class shooters tend to use either (both) approaches.

Ultimately, the key to successful testing may not necessarily be which approach you choose, but how carefully you carry out the testing and interpretation. Clearly the discipline you intend to shoot should influence your choice of methods. But it's also important to point out that with any method, testing increments cannot be too coarse, or the information you get in return is limited at best (i.e where is a given load actually located within some optimal window?). On the other hand, testing exceedingly small increments on the first pass when all you're really looking for is the right neighborhood to test further can sometimes be a waste of time and effort. I think most people try to find an acceptable balance between the two, and it may take time and experience to know in advance where that balance may be.

Regardless of the approach you choose, your initial charge weight testing should cover a sufficient charge weight range to reveal at least one potential accuracy node, maybe two or more. So you can certainly use a coarser charge weight increment such as 0.5 gr to cover a wider overall range initially and minimize the total number of rounds necessary. Regions that look promising can then be tested further in small increments to better define the boundaries of any "optimal" window you find.

Even if I don't use it, I understand the reasoning behind a "10-round" load development approach. I also have no doubt there are those that have been very successful and satisfied with this approach. However, I have gotten the feeling as this thread has progressed that you are becoming more and more lost with the process of load development. Maybe it's time to think less about the total number of rounds used for testing and focus more on a methodical stepwise and incremental approach, regardless of how many rounds it takes.

Your groups at 42.5 gr above give you a good starting reference point, even if you decide to change brass. For that reason, I would suggest trying to reproduce the 42.5 gr grouping and velocity. Changing brass will likely change case volume and therefore pressure/velocity. However, the expected changes shouldn't be huge, as 2-3 gr. It's far more likely you will observe a more subtle change. So use your 42.5 gr load as a reference or starting point, and test in finer increments (maybe 0.2 gr per test point) on either side of that, making sure you cover a sufficiently wide window in the process. I doubt you would need to test more than about 0.6 gr to either side to fully cover the window, even if it has shifted slightly to one side or the other due to using the Hornady brass. Further, your previous velocity at 42.5 gr will also be a good indicator as to what the switch to Hornady brass accomplished. Unless I'm mistaken, the Hornady brass should have greater case volume than Lapua. Therefore, you would anticipate achieving slightly lower velocity at a given charge weight. If that assumption holds, you'd know right away that you're going to need more than 42.5 gr to hit the same velocity, and can adjust the test window accordingly, if necessary. Once you find similar grouping with the new brass, you can move on to a seating depth test, at which point you ought to be close to where the rifle is shooting optimally.

Thank you for such a detailed response.

I wouldn’t say I’m lost. I enjoy the process and am gathering data in the mean time. My quest began to find the most efficient method to do so.

So starting with different brass and a different bullet, going from the hornady 140 HPBT to the 143 Eldx.

Based on all the info gathered thus far on this thread here is my plan.

Using Lapua Brass, cci srm primers, 143 eldx, and h4530, try a similar method to my original “10 round” and shoot three of each load in the ladder test. Also instead of shooting them all into one hole, I will shoot each load into its own group over a chronograph. This is a mix of the ladder test and ocw.

My plan is to start at 41.0 and load in .2gr incriminates up to 42.8.

Have I interpreted all the info correctly?

 

[Sraw]

From my observation, and your unexplained poi shift from a different day and those group shapes, youd be way money ahead and cut the learning curve by investing in some wind flags. Perfect practice makes perfect.

I appreciate the advice but there was no wind today or yesterday. I do agree that I need practice reading it though.

 

[Sraw]

Any signs of pressure ?

No

May I ask why 42.5 over 42.6

Absolutely, I’m wanting to stay in the middle of the velocity node. I even considered 42.4. 42.7 it where things start to be a little more erratic so I figured the .4 or .5 would be the safest bet due to the stability between .3 and .6.

 

[JFrank]

Makes sense
Can I ask another question?

 

[Sraw]

Makes sense
Can I ask another question?

Ask away.

 

[JFrank]

I actually like 42.5 as well, being in the middle of the obvious node.

1- I also count 12 initial shots and 28 on the last test.

2- I believe you could have done this test in 5 shots starting at 42.0 grains
3-Q Is why start the ladder at .020 jump?

 

[Baer45]

I think what he's trying is the method described here:

And more generally here:

https://www.youtube.com/results?search_query=satterlee+load+development+method

I think it's more of a short cut for experienced reloaders that are familiar with a given cartridge and know pretty much where they should end up. More of a verification of an existing 'pet' load in a new barrel/gun than full-on load tuning. Some people swear by it; others swear at it...

Personally I've seen enough variability in chronograph readings from one day to the next, with the *same* load, to have my doubts...

I have also done the “10 round” load development test and found it useful as an educational experience. I still prefer to shoot some type of a ladder for load development because the 10 rd did not always give me difinitive enough info. I asked a couple of custom rifle builders and a handful of PRS shooters and their feedback to me was the “10 step” tended to work better with smaller caliber/charges but was unreliable when going to h4350 at 40 gr and above (example)... it would be nice to keep the barrel wear to a minimum with 10 shots

 

[Sraw]

I actually like 42.5 as well, being in the middle of the obvious node.

1- I also count 12 initial shots and 28 on the last test.

2- I believe you could have done this test in 5 shots starting at 42.0 grains
3-Q Is why start the ladder at .020 jump?

The only reason for it showing 12 is that’s all the graph app I had would allow. I actually did 15 I believe. The others were below my velocity goal so I ruled them out. The reason I did 15 instead of 10 was simply to cover more ground because I had no experience with this caliber or rifle.

I agree, I could have done it in 5 shots if I knew that is exactly where the node was. This way showed me 2 nodes at different ends of the spectrum.

.020 off the lands was chosen after reading several places it is a well liked distance. In hind sight I might have started at .010 so I could back off if needed rather than moving up and back but it’s 6 of one and a half dozen of another. The precision hunter loading from Hornady is very well respected factory load and jumps .070 or more so while i plan to explore seating depth to fine tune my load, I’m more so doing it for additional data.

 

[JFrank]

Always good to have data.
Thank you now I know"

 

[Ned Ludd]

Thank you for such a detailed response.

I wouldn’t say I’m lost. I enjoy the process and am gathering data in the mean time. My quest began to find the most efficient method to do so.

So starting with different brass and a different bullet, going from the hornady 140 HPBT to the 143 Eldx.

Based on all the info gathered thus far on this thread here is my plan.

Using Lapua Brass, cci srm primers, 143 eldx, and h4530, try a similar method to my original “10 round” and shoot three of each load in the ladder test. Also instead of shooting them all into one hole, I will shoot each load into its own group over a chronograph. This is a mix of the ladder test and ocw.

My plan is to start at 41.0 and load in .2gr incriminates up to 42.8.

Have I interpreted all the info correctly?

I think that's a good plan, but I would suggest using either the ladder OR OCW approach, not a combination/mix of both. The rest range and increment size you have indicated are appropriate. If you like the ladder approach, I would suggest that you simply shoot two or three separate (but otherwise identical) single shot ladder targets. Having multiple (but separate) ladders to look over should provide you with the desired answers of where your nodes are with respect to charge weight. If you prefer the OCW approach, I'd follow Erik Cortina's methodology exactly. Good luck with it.

 

[Sraw]

I think that's a good plan, but I would suggest using either the ladder OR OCW approach, not a combination/mix of both. The rest range and increment size you have indicated are appropriate. If you like the ladder approach, I would suggest that you simply shoot two or three separate (but otherwise identical) single shot ladder targets. Having multiple (but separate) ladders to look over should provide you with the desired answers of where your nodes are with respect to charge weight. If you prefer the OCW approach, I'd follow Erik Cortina's methodology exactly. Good luck with it.

I will look up Eric’s method, thanks.

Just to appease my curiosity, why would 3 individuals be better than one test with 3 of each?

What are your thoughts on the, say 3, separate ladder tests being shot on the same 10 targets (1 per load)?

I know this isnt how to yield the best groups due to changes in position but wouldn’t it provide an opportunity for additional data if a good group was found in the middle of a velocity (or elevation) node? The bullets have to go somewhere.

If I am not being clear, I mean shooting something like the following:

Load 1 of test 1-target 1
Load 2 of test 1-target 2
Load 3 of test 1-target 3
Etc, etc, etc....

Load 1 of test 2-target 1
Load 2 of test 2-target 2
Load 3 of test 2-target 3
Etc, etc, etc....

Load 1 of test 3-target 1
Load 2 of test 3-target 2
Load 3 of test 3-target 3
Etc, etc, etc....

Thanks.

 

[BoydAllen]

I appreciate the advice but there was no wind today or yesterday. I do agree that I need practice reading it though.

The people who have and regularly use wind flags are shaking their heads about now.

 

[Sraw]

The people who have and regularly use wind flags are shaking their heads about now.

I can imagine my comment sounds a little ignorant but my range is lined with trees with one having branches hanging over the 100 yard target board. I usually try to use them as a guide, leaves were still today...

 

[Ned Ludd]

One is not necessarily better than the other. The issue with performing multiple ladders shot on the same target is if you can't correlate all the bullet holes with their respective loads. There are ways around this, such as coloring the bullets with a Sharpie so the smudges around the bullet holes are also colored. However, that doesn't always work perfectly. Shooting the same identical set of [ladder] rounds on two or three different targets is the easiest way to be sure you can discriminate which bullet hole goes with which load. Of course, you still have to keep track of each hole as you shoot by some method. Two or more replicates of the same ladder test on different targets may simply allow you to better distinguish any individual shots that might be errant in terms of their expected vertical displacement on the target.

No matter how you do it, there is always a certain minimum degree of shot dispersion that is normally expected at some given distance. That normal shot dispersion includes vertical, which can sometimes make a ladder more difficult to interpret if a key shot that should have been coincident on the target vertically with a couple other charge weights is actually the one that is off high/low. For example, let's say you have a single shot representing the middle of three successive charge weights that should actually show positive compensation, and thus all three shots should hit the target at about the same elevation. But for whatever reason (i.e pulled shot, gust of wind, etc.), that one shot goes high or low. Now you will not so easily be able to define that charge weight window because the middle shot is way off, vertically. In such a case, having at least a couple replicates where you can clearly identify each specific bullet hole can sometimes be beneficial to interpreting the results, because it is unlikely that you will have the same problem with just one shot representing the exact same load being "out" on both targets. It's just improving your odds, if you like. If I understand your testing approach outlined above, that is exactly what I'm talking about. However you achieve it, the goal is to know with certainty which bullet hole corresponds to which load.

When using Erik Cortina's approach, the idea is to shoot 3-shot groups and look for two or three groups for successive charge weights where the centerpoint of the group does not move with respect to the point of aim. Note that Erik's method does not depend on the size (spread) of each individual group, only the relative position of the group centerpoint. Like a ladder test in which different elevation (vertical) of a bullet hole is associated with different charge weights, Erik's approach also uses movement of the group centerpoint on the target as a readout. The difference is that with Erik's method, two or three successive charge weights that don't move the group centerpoint indicate a minimal response to changing charge weight in terms of point of impact (POI). In other words, the POI is minimally sensitive to charge weight within a given window. The middle of that window is where you want to be.

Link to Erik's Test Method:
http://forum.accurateshooter.com/threads/long-range-load-development-at-100-yards.3814361/

On a ladder test, you're looking for at least two or three successive charge weights that print their individual bullet holes at very close to the same elevation on the target. That means that vertical dispersion is minimal within that particular charge weight window (i.e. positive compensation). Successive charge weights that print bullet holes far apart vertically are not desirable because that means your elevation will be much more sensitive to even minor variance in charge weight and/or velocity.

 

[Link]

I thought when you shoot a ladder you load up until you see signs of pressure, then back off ? What if there is a good node over your max load ?

 

[JFrank]

I thought when you shoot a ladder you load up until you see signs of pressure, then back off ? What if there is a good node over your max load ?

It wouldn't be a good node at that point. IMO

 

[steve123]

I thought when you shoot a ladder you load up until you see signs of pressure, then back off ? What if there is a good node over your max load ?

Less barrel life and brass life, not great for bolt face etching either. Lookout when a hot day comes!!! Bring a rubber mallet.

 

[BoydAllen]

I can imagine my comment sounds a little ignorant but my range is lined with trees with one having branches hanging over the 100 yard target board. I usually try to use them as a guide, leaves were still today...

If you go to a short range benchrest match, you will see a forest of wind flags. The one place that you will not see them is at the target. Generally, you will see four when the targets are at 100 yards. Locally, because of prevailing conditions, the nearest one will be 10-15 yards from the bench. The closer to the bench that a cross wind is, the more influence it will have at the target. Do a little experiment. Get a roll of surveyors' tape and some 4' pieces of 1x2. Sharpen one ends of the 1x2s and attach lengths of the tape to the other ends, long enough so that they hang to just above the ground with the stakes driven in enough so that they will not be blown over. Put one at ten yards, the next at thirty, the next one at fifty and the last one at seventy (all approximate) and watch them for a while. You may be surprised. Let us know what you discover. Generally, flags will not agree with each other down the line, at any given moment, but if you try to have them all in the same positions for each shot in a group, your groups will be smaller. None of us is born knowing this stuff.

 

[fredo]

OP: for the intent of your testing, don't sweat flags/wind. Just do your best to shoot @ same conditions, and basically ignore horizontal dispersion, as it pertains to group size. I'll get piled on for that, but for simplicity's sake, leave it be. Getting into a debate on the finer points of 'flag reading' isn't what you're lookin' for, anyway...

The whole point of incremental testing is to indentify charge weights that minimize vertical dispersion. The wind gone do what it gone do! So, short of a switchy galeforce head/tailwind, stay focused on breaking a clean shot with consistent form. And again, trust the target & don't be seduced by the chronograph!

Most important, be safe & have fun!!!