What would be considered a minimum # of loads to properly do a ladder test. I have a gap 7wsm that shoots great (less than 1/2 moa) with 63g H4831sc and 180 bergers. I found this load shooting various groups around what George Gardner told me was a good load (62.5g H4831sc 180 bergers). I have recently been reading up on ladder testing after Jared Joplin explained it to me and want to try it just to see. My problem is, I am not going to shoot this gun below 61 grains, so why ladder test anything below that. If I start @ 61 then 61.5, 62, 62.5 and stop @ 63 (I don't want to go any hotter), thats only 5 loads. I don't think you would see the nodes with only 5. Let me know what you think. Thanks
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minimum # of loads for a ladder test?
- Thread starter CCooper
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Re: minimum # of loads for a ladder test?
CCooper,
I use four loads with the 0.5 grain steps, five if I want a close data set. A close data set uses loads 0.2 or 0.3 grain steps for the powder charge. You should get enough data to get close to a node with what you are planning. Load up ten of the lightest load, you'll want some rounds to warm up and foul the barrel before shooting for groups. Use five to seven rounds per group.
HTH,
DocB
CCooper,
I use four loads with the 0.5 grain steps, five if I want a close data set. A close data set uses loads 0.2 or 0.3 grain steps for the powder charge. You should get enough data to get close to a node with what you are planning. Load up ten of the lightest load, you'll want some rounds to warm up and foul the barrel before shooting for groups. Use five to seven rounds per group.
HTH,
DocB
Re: minimum # of loads for a ladder test?
Keep in mind that a ladder test has approx 1/3 chance of a given load not representing properly due to the 'scatter node' effect of barrel harmonics.
Have you checked out "optimal charge weight" load development? I've switched to that and won't do another ladder.
Keep in mind that a ladder test has approx 1/3 chance of a given load not representing properly due to the 'scatter node' effect of barrel harmonics.
Have you checked out "optimal charge weight" load development? I've switched to that and won't do another ladder.
Re: minimum # of loads for a ladder test?
The ladder test, if done unmodified has the disadvantage of starting with a low charge one wouldn't consider and could be considered a waste of powder and bullets.
I studied the OCW method and decided to go with the ladder method. Both methods are used by top shooters but I decided to listen to a well known 1K shooter who swears the ladder is more favorable for rifles capable of shooting SUB-MOA consistantly. Thats their argument, not mine.
To answer the question:
I managed to load eight rounds for my 300WM. I loaded two of each charge to confirm the results of the first group. I understand some do more. I don't shoot competition therefore the twenty suited me fine.
I was happy with my results and found a distintive node that I furthered tweaked with success.
The ladder test, if done unmodified has the disadvantage of starting with a low charge one wouldn't consider and could be considered a waste of powder and bullets.
I studied the OCW method and decided to go with the ladder method. Both methods are used by top shooters but I decided to listen to a well known 1K shooter who swears the ladder is more favorable for rifles capable of shooting SUB-MOA consistantly. Thats their argument, not mine.
To answer the question:
I managed to load eight rounds for my 300WM. I loaded two of each charge to confirm the results of the first group. I understand some do more. I don't shoot competition therefore the twenty suited me fine.
I was happy with my results and found a distintive node that I furthered tweaked with success.
Re: minimum # of loads for a ladder test?
I had a wise sage recently suggest .4 grn increments.
Anyone have a link to read up on the "OCW method"? I've heard about it, but don't know the what or how?
I had a wise sage recently suggest .4 grn increments.
Anyone have a link to read up on the "OCW method"? I've heard about it, but don't know the what or how?
Re: minimum # of loads for a ladder test?
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: ReaperDriver</div><div class="ubbcode-body">I had a wise sage recently suggest .4 grn increments.
Anyone have a link to read up on the "OCW method"? I've heard about it, but don't know the what or how? </div></div>
OCW:
http://optimalchargeweight.embarqspace.com/#/ocw-vs-ladder/4529811360
Some ladder info:
http://www.6mmbr.com/laddertest.html
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: ReaperDriver</div><div class="ubbcode-body">I had a wise sage recently suggest .4 grn increments.
Anyone have a link to read up on the "OCW method"? I've heard about it, but don't know the what or how? </div></div>
OCW:
http://optimalchargeweight.embarqspace.com/#/ocw-vs-ladder/4529811360
Some ladder info:
http://www.6mmbr.com/laddertest.html
Re: minimum # of loads for a ladder test?
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: wadevb1</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: ReaperDriver</div><div class="ubbcode-body">I had a wise sage recently suggest .4 grn increments.
Anyone have a link to read up on the "OCW method"? I've heard about it, but don't know the what or how? </div></div>
http://optimalchargeweight.embarqspace.com/#/ocw-vs-ladder/4529811360 </div></div>
Thanks! WIll read up on it tonight, as I still <span style="text-decoration: line-through">some </span>a lot of load testing to do
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: wadevb1</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: ReaperDriver</div><div class="ubbcode-body">I had a wise sage recently suggest .4 grn increments.
Anyone have a link to read up on the "OCW method"? I've heard about it, but don't know the what or how? </div></div>
http://optimalchargeweight.embarqspace.com/#/ocw-vs-ladder/4529811360 </div></div>
Thanks! WIll read up on it tonight, as I still <span style="text-decoration: line-through">some </span>a lot of load testing to do
Re: minimum # of loads for a ladder test?
With OCW, I was able to dial in a really robust 75-grain HPBT load for my rifle with 15 rounds.
With the 'scatter node' phenomenon, the powder blast exits the barrel at the same time as the bullet, creating a 1-in-3 chance that THAT particular powder charge appears to be in the sweet spot of a ladder development, when it is in fact NOT.
The nice thing about OCW is once you find your accuracy node (typically 1-2% above your scatter node), then it is more insensitive to temp variations as well as slight powder charge differences. THAT is why I refer to it as a 'robust' load.
With OCW, I was able to dial in a really robust 75-grain HPBT load for my rifle with 15 rounds.
With the 'scatter node' phenomenon, the powder blast exits the barrel at the same time as the bullet, creating a 1-in-3 chance that THAT particular powder charge appears to be in the sweet spot of a ladder development, when it is in fact NOT.
The nice thing about OCW is once you find your accuracy node (typically 1-2% above your scatter node), then it is more insensitive to temp variations as well as slight powder charge differences. THAT is why I refer to it as a 'robust' load.
Re: minimum # of loads for a ladder test?
This is an OCW for a 300 WM. The rifle is a Mauser action with a 26" Douglas SS target barrel. It has a wood stock which is now fully glass bedded.
The OCW was shot with 168 grain Nosler HPBT and IMR 4350. The range was 300 yards with some wind from 140 degrees. There are 10 groups, with 0.3 grain increases, starting at the upper left with 68.0 grains. The shot group is always above the 1” red square. This was my first surprise. I had previously loaded some identical rounds with 68.0 grains of IMR4350 to use to get on the paper and establish where I wanted the groups to be on the target. I was using old Remington brass for these loads. The POI was zero elevation and about 2” right at 300 yards. Shot a three shot 1 1/4” group. Was pleased with this group at 300 yards. The OCW loads used brand new Nosler brass (2nds). The impact of the 68.0 grain charge with Nosler brass was three inches higher than the identical rounds with Remington brass and the groups stayed high over the course of the test. I don't think I will shoot >1,000 yards. I believe that anything >3,000 fps will get me to 1,000 yards supersonic. So a node in the 68-69 grain range may do what I want. I also want to save the 300 WM barrel. I looked at the center to center measurement of each group and also at the elevation spread within each group. I understand the change in elevation is a good indication of the robustness of the rifle and its loads with regard to locating its sweet spot. The target photos and the data follow.
This group center to center was 2.3 inches. The elevation was 0.1 MOA.
This group center to center was 2.5 inches. The elevation was 0.2 MOA.
This group center to center was 4.3 inches. The elevation was 0.4 MOA.
This group center to center was 3.8 inches. The elevation was 0.8 MOA.
This group center to center was 2.8 inches and the elevation was 0.2 MOA. The group beside it was center to center was 3.8 inches. The elevation was 0.3 MOA.
This group center to center was 3.1 inches. The elevation was 0.6 MOA.
This group center to center was 2.4 inches. The elevation was 0.5 MOA.
This group center to center was 2.3 inches. The elevation was 0.4 MOA.
This group center to center was 3.5 inches. The elevation was 0.6 MOA.
This is the data.
Looks like I need to start refining the load around 68.3 grains. Looks like the old girl is carrying them pretty good.
This is an OCW for a 300 WM. The rifle is a Mauser action with a 26" Douglas SS target barrel. It has a wood stock which is now fully glass bedded.
The OCW was shot with 168 grain Nosler HPBT and IMR 4350. The range was 300 yards with some wind from 140 degrees. There are 10 groups, with 0.3 grain increases, starting at the upper left with 68.0 grains. The shot group is always above the 1” red square. This was my first surprise. I had previously loaded some identical rounds with 68.0 grains of IMR4350 to use to get on the paper and establish where I wanted the groups to be on the target. I was using old Remington brass for these loads. The POI was zero elevation and about 2” right at 300 yards. Shot a three shot 1 1/4” group. Was pleased with this group at 300 yards. The OCW loads used brand new Nosler brass (2nds). The impact of the 68.0 grain charge with Nosler brass was three inches higher than the identical rounds with Remington brass and the groups stayed high over the course of the test. I don't think I will shoot >1,000 yards. I believe that anything >3,000 fps will get me to 1,000 yards supersonic. So a node in the 68-69 grain range may do what I want. I also want to save the 300 WM barrel. I looked at the center to center measurement of each group and also at the elevation spread within each group. I understand the change in elevation is a good indication of the robustness of the rifle and its loads with regard to locating its sweet spot. The target photos and the data follow.
This group center to center was 2.3 inches. The elevation was 0.1 MOA.
This group center to center was 2.5 inches. The elevation was 0.2 MOA.
This group center to center was 4.3 inches. The elevation was 0.4 MOA.
This group center to center was 3.8 inches. The elevation was 0.8 MOA.
This group center to center was 2.8 inches and the elevation was 0.2 MOA. The group beside it was center to center was 3.8 inches. The elevation was 0.3 MOA.
This group center to center was 3.1 inches. The elevation was 0.6 MOA.
This group center to center was 2.4 inches. The elevation was 0.5 MOA.
This group center to center was 2.3 inches. The elevation was 0.4 MOA.
This group center to center was 3.5 inches. The elevation was 0.6 MOA.
This is the data.
Looks like I need to start refining the load around 68.3 grains. Looks like the old girl is carrying them pretty good.
Re: minimum # of loads for a ladder test?
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: wadevb1</div><div class="ubbcode-body">The ladder test, if done unmodified has the disadvantage of starting with a low charge one wouldn't consider and could be considered a waste of powder and bullets.
I studied the OCW method and decided to go with the ladder method. Both methods are used by top shooters but I decided to listen to a well known 1K shooter who swears the ladder is more favorable for rifles capable of shooting SUB-MOA consistantly. Thats their argument, not mine.
To answer the question:
I managed to load eight rounds for my 300WM. I loaded two of each charge to confirm the results of the first group. I understand some do more. I don't shoot competition therefore the twenty suited me fine.
I was happy with my results and found a distintive node that I furthered tweaked with success.
</div></div>
I completely agree with you on the low charge issue. I have decided to do the same with my 6.5x47 regarding loading 2 loads of each charge and doing 2 ladder tests back to back to see how similar the results are. If they are similar, then I will be impressed by the ladder procedure, If not, I may research the OCW procedure more. Thanks for the help everyone.
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: wadevb1</div><div class="ubbcode-body">The ladder test, if done unmodified has the disadvantage of starting with a low charge one wouldn't consider and could be considered a waste of powder and bullets.
I studied the OCW method and decided to go with the ladder method. Both methods are used by top shooters but I decided to listen to a well known 1K shooter who swears the ladder is more favorable for rifles capable of shooting SUB-MOA consistantly. Thats their argument, not mine.
To answer the question:
I managed to load eight rounds for my 300WM. I loaded two of each charge to confirm the results of the first group. I understand some do more. I don't shoot competition therefore the twenty suited me fine.
I was happy with my results and found a distintive node that I furthered tweaked with success.
</div></div>
I completely agree with you on the low charge issue. I have decided to do the same with my 6.5x47 regarding loading 2 loads of each charge and doing 2 ladder tests back to back to see how similar the results are. If they are similar, then I will be impressed by the ladder procedure, If not, I may research the OCW procedure more. Thanks for the help everyone.
Re: minimum # of loads for a ladder test?
CCooper:
If you are already getting the velocity range that you are looking for, and if you already have a load that reliably shoots .5moa, then I think you're done with load developing. the 300WSM is not a 6ppc shooting short range benchrest, and if your load is doing .5moa most every time, then load it up and spend your time and efforts practicing and shooting, and not on the reloading bench. You'll probably get more return on your time, bullets, and barrel life that way.
CCooper:
If you are already getting the velocity range that you are looking for, and if you already have a load that reliably shoots .5moa, then I think you're done with load developing. the 300WSM is not a 6ppc shooting short range benchrest, and if your load is doing .5moa most every time, then load it up and spend your time and efforts practicing and shooting, and not on the reloading bench. You'll probably get more return on your time, bullets, and barrel life that way.
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