New (kinda) technique to develop a load

[lisagrantb]

so I was thinking at work a while back on how to develop a load for a new 338 Lapua I was getting. Do I do the ocw or ladder method, then I thought why not do both at the same time. I mean there basically the same test just done at different ranges. I have access to a 1k range near me so I waited for the perfect day, no wind at all and overcast with no mirage. I set everything up, fired a few sighters then ran the test. I gathered the data threw it in a spreadsheet (at work of course) and here are the results. It kinda surprised me at the outcome.

 

[ar10ar15man]

they are not the same test.
range does not separate the two.
a ladder is just the first STEP in load development.
it is intended to help find nodes in your RIFLE with your bullet and powder.
the round robin testing of bsocw just adds variables, cost time and money.

never in a bench rest match have i seen targets shot in rotation. they shoot one target then the next..."no rotation"
ccw was created by a person that did not understand how to develop loads period.

View attachment 126597 so I was thinking at work a while back on how to develop a load for a new 338 Lapua I was getting. Do I do the ocw or ladder method, then I thought why not do both at the same time. I mean there basically the same test just done at different ranges. I have access to a 1k range near me so I waited for the perfect day, no wind at all and overcast with no mirage. I set everything up, fired a few sighters then ran the test. I gathered the data threw it in a spreadsheet (at work of course) and here are the results. It kinda surprised me at the outcome.

 

[ar10ar15man]

do you have the target of the first 6 shots( the part closest to a ladder )?
charts and graphs are nice,,,but TARGETS are the actual hits.
shooting groups round robin are not statistically relevant.

 

[LongBomber]

It is an interesting way to test, that all of your data shows improved numbers around the 93gr mark would show that you are in a "node" at that point. I wonder if the testing would show better data if done in .5gr or less steps at that distance.

 

[jasonco]

I'm having trouble trying to see a correlation, if there is one

A target image would be of great help...

 

[Barrelnut]

Nice. Agree with LongBomber, 93 seems to be the spot. The graphs show a good visual confirmation. I don't think it is really has a ladder test component.
Would e interesting to see how repeatable it is.

 

[ar10ar15man]

i think that she is good with 1 gr till closer to a node. a ladder is done at 1/100 of case capacity. 1 is a good number for that case.
lots of bullets and powder gone and not sure if she found a node.

It is an interesting way to test, that all of your data shows improved numbers around the 93gr mark would show that you are in a "node" at that point. I wonder if the testing would show better data if done in .5gr or less steps at that distance.

 

[lancetkenyon]

To me, that just looks like you were shooting for groups @ 1000 over a chrono. Not a ladder test. But 93.0gr seems like, for those 3 rounds at least, a good place to explore. Is it repeatable? Time will tell.

 

[dsculley]

Actually, the OCW method works very well. The "round robin" is designed to spread the shots across the shooting session so that all groups are shot in similar conditions (If you shot a 3 shot group ,then another, then another, changes in winds, lighting and shooter fatigue can affect the result). It is also designed to cancel one of the largest potential downfalls of the ladder test: If you pull a shot and don't realize it this can cause erroneous assumptions in the results. You shoot the OCW at 100 yds to minimize wind effects. When both the Audette Ladder and the OCW are shot correctly they provide the same result: You are looking for an area where the change in powder does not result in a corresponding change in vertical - a flat spot.

Dan Newberry, the developer of the OCW method, is an accomplished shooter and is a very good instructor. He as a long range shooting school - Bangsteel.com. His school is well worth the time and money!

Trying to combine the two is nothing new. People have tried to adapt these methods so suit their personal whim, sometimes with good results and sometimes not. I personally first test for seating depth using the Berger method. Next, I shoot the OCW test. I then verify the load at range using a small ladder testing a smaller area around the indicated charge. I recently tested my current 6.5x47 load (Developed using the OCW method) by loading two rounds each at 38.5, 38.6 (my go-to load) and 38.7. I shot all six at 287 yds (the longest range available) and all 6 were in a 0.45 moa group (0.38 Vertical). I pulled one shot and it was low and left but it was included in the group measurement. If I had excluded the called flier the other five measured 0.2 moa (0.13 Vertical).

This

 

[wildcat455]

If it is repeatable, I think the OP should call this method of testing the CTTC method. (Cut To The Chase)

At first glance it looks like OP was shooting for groups, but there is data there that supports the OP has a load with low vertical, good ES and SD, and good grouping size.

Isn't that really what we all are looking for?

Not sure why the critical, opposition, or "devil's advocate" replies to this?
OP found a load in 18 rounds definitely worth exploring further.

If I were the OP, my next step would be same format of testing, centered around 93 gr. From 92.5 to 93.5, to try to find the center of the node showing at 93 in this test.

OP, what bullet, case, primer, and powder?

 

[Bob Wright]

So I tried the OCW test with RE22 and RE23. While RE22 had clear flat spots (sills?) at 60 to 61 and 62 to 62.5 grains,
RE23 was just a steady velocity increase at each sample weight of powder. What to do?
I just had to go to the range and shot 2 foulers, 3 shots at 62.2 , then 3 shots at 63.2. Max charge I called at 63.8 gr, which was the RE22 value from Nosler, as I had no actual load data from Nosler using RE23.
Admittedly, I need to go back and finish the load workup so this is preliminary. I think OCW has merit as it does limit excess shooting if you know how to read the results. Can't say I do, as this was my first crack at it.

 

[ar10ar15man]

lots of burned powder, and bullets and no answer...ocw at work...lol

So I tried the OCW test with RE22 and RE23. While RE22 had clear flat spots (sills?) at 60 to 61 and 62 to 62.5 grains,
RE23 was just a steady velocity increase at each sample weight of powder. What to do?
I just had to go to the range and shot 2 foulers, 3 shots at 62.2 , then 3 shots at 63.2. Max charge I called at 63.8 gr, which was the RE22 value from Nosler, as I had no actual load data from Nosler using RE23.
Admittedly, I need to go back and finish the load workup so this is preliminary. I think OCW has merit as it does limit excess shooting if you know how to read the results. Can't say I do, as this was my first crack at it.

 

[Texanjohn]

lots of burned powder, and bullets and no answer...ocw at work...lol

Perhaps if you looked at OCW as a viable test, took the time to read and understand the basic principles of round robin shooting, you would not come off as such an ?!..,,@#$

 

[lisagrantb]

Lapua brass fed215m Berger 300 otm and retumbo. I have another graph that shows the group centers for each charge weight plotted on a quadratic chart and it tells the story of the ocw method (at 1k yards). I think the issue with doing this method is having a range available for the perfect day to run the test no wild or mirage.