No
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.
Very happy so far, “10 round” load development results.
- Thread starter Sraw
- Start date
No
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.
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
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.
Ned Ludd
Silver $$ Contributor
I think that's a good plan, but I would suggest using either the ladder OR OCW approach, not a combination/mix of both. The rest range and increment size you have indicated are appropriate. If you like the ladder approach, I would suggest that you simply shoot two or three separate (but otherwise identical) single shot ladder targets. Having multiple (but separate) ladders to look over should provide you with the desired answers of where your nodes are with respect to charge weight. If you prefer the OCW approach, I'd follow Erik Cortina's methodology exactly. Good luck with it.
I will look up Eric’s method, thanks.
Just to appease my curiosity, why would 3 individuals be better than one test with 3 of each?
What are your thoughts on the, say 3, separate ladder tests being shot on the same 10 targets (1 per load)?
I know this isnt how to yield the best groups due to changes in position but wouldn’t it provide an opportunity for additional data if a good group was found in the middle of a velocity (or elevation) node? The bullets have to go somewhere.
If I am not being clear, I mean shooting something like the following:
Load 1 of test 1-target 1
Load 2 of test 1-target 2
Load 3 of test 1-target 3
Etc, etc, etc....
Load 1 of test 2-target 1
Load 2 of test 2-target 2
Load 3 of test 2-target 3
Etc, etc, etc....
Load 1 of test 3-target 1
Load 2 of test 3-target 2
Load 3 of test 3-target 3
Etc, etc, etc....
Thanks.
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BoydAllen
Gold $$ Contributor
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
Silver $$ Contributor
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.
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.
Less barrel life and brass life, not great for bolt face etching either. Lookout when a hot day comes!!! Bring a rubber mallet.
BoydAllen
Gold $$ Contributor
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.
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!!!
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!!!
memilanuk
Gold $$ Contributor
Actually... no.
While there are some full-sized IPSC targets or other 'large'ish targets in some courses of fire, any 'slop' is offset by drastically reduced time limits and/or (usually 'and') non standard firing positions. Their loads don't have to be 'BR' accurate for 5 shots, or 'F-class' consistent for 20+... but if you think their targets don't require a fair degree of accuracy, I'd invite you to go actually try one out before making more comments like that.
About the 10-shot method in general:
I think I either said (or implied) this before: this method is a short cut - for *experienced* shooter/reloaders. If you have a known good load in a given caliber, and you replace the barrel (for the second or third time this year alone)... do you think you *really* need to do a full-blown load workup? Probably not... you know what you need to see, you know where the sweet spot, the perfect 'node', the honey hole, etc. is. This method is a short-cut for people like that to get their competition gun up and running as quickly as possible while conserving as much competitive barrel life. I've done my own version of it when spinning up (yet another) .308 barrel for FTR - after three or four barrels sacrificed on the altar of Berger 200H/200.20X bullets, I have a pretty decent idea where I want to be velocity-wise. I may not be doing it in 10 shots (or 12), but I can find it a whole lot quicker than when I first started with that combination. And if I have to change component lots for some reason... I can just about re-tune the load using just the chrono - I know where it needs to be. I'll still confirm it on paper, of course, but thats different than doing complete workup on paper from start to finish every single time. Some people dig that stuff, and more power to them.
Unfortunately, a whole bunch of new-ish shooters and loaders around the internet have latched onto this method, seeking to shortcut and avoid actually learning traditional load development methodology. Most of them would be (in my opinion) better served by going back to either a basic OCW test, or something like the 100yd Load Development thread by @Erik Cortina . I know nobody wants to hear that, but that doesn't make it not true.
Ok that makes a little more sense. So if I understand you correctly I’d be using the 10 rounds to locate which load the new barrel pushes a specific bullet, which is known to shoot well at a general velocity, at that velocity, and then develop from there?
Jumping into the conversation late, but I agree with the prior comments that you want more than just velocity data when doing load development. I like to follow a combination of OCW and Satterlee method, looking for both consistent POI on target as well as velocity flat spot, any indicators of good/bad SD, and also group size as a whole. I'll shoot OCW style 3 shot groups using a chrono that doesn't touch the barrel, and can get all the info I want out of 15-18 shots. I'll do a final test with seating depth, if needed. If you don't have a free floating chrono, I like loading 2 extra rounds and using those to get velocity info and shoot the OCW without anything on the barrel.
Here's what a typical target and velocity data looks like, from my last 6BRA barrel. You can see that the velocity info (average of 3 shots) did not show a clear "flat spot" but the target showed a nice POI consistency and good groups in the 31.4 to 31.6 range. If I'd tried to get just velocity info I wouldn't have been able to see the load nearly as easily.
Here's what a typical target and velocity data looks like, from my last 6BRA barrel. You can see that the velocity info (average of 3 shots) did not show a clear "flat spot" but the target showed a nice POI consistency and good groups in the 31.4 to 31.6 range. If I'd tried to get just velocity info I wouldn't have been able to see the load nearly as easily.
CharlieNC
Gold $$ Contributor
Looking at the individual data points on the velocity plot, it is apparant that you could pick one of those which would then appear to give a "flat spot" and be misled. It is probably surprising to most that a single shot when doing a ladder test on a target is usually more definitive and consistent than a corresponding single chrono test when it comes to defining a node. Not to mention that the barrel vibrations which lead to a target node have nothing to do with velocity as a mechanism. Velocity variability can reflect a problem, but not a node.
Very true. And this is on a cartridge that has SD's in the low single digits. It would only be more difficult and prone to error on a cartridge with an SD of 10 or 15.
I actually like this a lot. I think this is where I should have started and will start for this next test.
The only difference, and I’m sure many will hate this, is after a few tests I have found there is no detectable difference in how the barrel shoots with and without the chrono hanging off it. Maybe each of my tests were flukes but in my quest for the most efficient load development process I plan to shoot the initial test with the chrono, identify the velocity flat spot if available, the vertical poi, and lastly the group size.
With this data I plan (hope) to narrow it down to one or two specific loads that I will shoot 5 to confirm velocity, and five without chrono to confirm grouping.
In this picture am I correct in 30.1 being the load you would pursue due to the elevation?
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Yup
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