Advice for interpreting ladder test results??

[Paulcobb]

I’ve always used ocw method for testing loads but decided to try my first ladder test on a .300 rum build. Test was done at 400 yards, no chrono just the paper ladder. 215 bergs with h1000.

can someone give any advice or insight to help decipher the results?

it seems that the 86.2-86.6 looks good but the 87-87.4-87.8 also looks interesting…

little puzzled on why 2 nodes would be so close together in powder charges.

thanks in advance!

 

[Harvey_NW]

I'd be starting at 87.4 for sure. I bet you're not far off with seating either, that 87gr group is better than some people can print at 100. I think the 86.2-86.6 could either be a fluke or an indication that you're on the edge, but that POI shift upward and the 87gr group speaks loudly to me.

 

[Rifles And More]

Advice - don't do a ladder test.

Looks like around that 87 somewhere.

 

[Paulcobb]

Advice - don't do a ladder test.

Looks like around that 87 somewhere.

what’s been your bad experiences with ladders? just wondering as this is the first time i’ve tried this approach.

 

[JRMiller]

Advice - don't do a ladder test.

Looks like around that 87 somewhere.

I concur. Not large enough control to go off.
I also dont do initial load development at something like 400 yards.
Fine tuning maybe yes, but not intial. Just my opinion.

 

[Rifles And More]

I think it's not statistically representative.

I do a version of the ten-shot velocity test - don't even care about groups. It's really the same thing you are doing, just looking for that velocity flat spot and starting from there.

I load sixty (10 six-shot groups) at .2 grain increments and start shooting over the magneto speed. Usually, I find pressure before they are all shot and break some back down.

I just did a 308 set and found a flat spot with a 4SD and 9ES over a six shop group. Now, I'll tune for group size at 100 yards with seating depth.

I'd rather see the numbers than read the chicken bones at 400 yards.

 

[Rifles And More]

...and

You are in there with the 87grain node, you are just gonna have to go back and do what I start with in order to find the sweet spot.

 

[Paulcobb]

I think it's not statistically representative.

I do a version of the ten-shot velocity test - don't even care about groups. It's really the same thing you are doing, just looking for that velocity flat spot and starting from there.

I load sixty (10 six-shot groups) at .2 grain increments and start shooting over the magneto speed. Usually, I find pressure before they are all shot and break some back down.

I just did a 308 set and found a flat spot with a 4SD and 9ES over a six shop group. Now, I'll tune for group size at 100 yards with seating depth.

I'd rather see the numbers than read the chicken bones at 400 yards.

what’s the thought on 100 yard vs 400 for load development? i’ve usually done 100 but it seems to me that 400 would be a more accurate representation of true barrel harmonics and velocity instead of trying to interpret very small 100 yard groups?

 

[Rifles And More]

I think 400 yards is not enough of a controlled environment. Distance adds variables.

At 100 yards those variables are minimized, but things are still dispersed enough to read the groups (vs. 50 for example).

I'd stick with 100 and then verify drops.

 

[Harvey_NW]

I disagree. Your test identified the scatter and velocity nodes you were looking for and I encourage you to follow through with the process because I bet you'll end up with a lights out load.

If these were my results, I would do a seating depth test at 87.4gr. Once you identify a jump node, you can further refine the load by testing powder charges in .1gr increments within that velocity node with a chrono. This is my preferred process, and I've never had it fail to either land me with an accurate and stable load or at least show me the potential of the combo without blowing through a large amount of components.

 

[Rifles And More]

Skinning a cat.

 

[Paulcobb]

I disagree. Your test identified the scatter and velocity nodes you were looking for and I encourage you to follow through with the process because I bet you'll end up with a lights out load.

If these were my results, I would do a seating depth test at 87.4gr. Once you identify a jump node, you can further refine the load by testing powder charges in .1gr increments within that velocity node with a chrono. This my preferred process, and I've never had it fail to either land me with an accurate and stable load or at least show me the potential of the combo without blowing through a large amount of components.

I’d like to finish this method as i’ve always wanted to try it hoping for a faster and less component heavy testing process. I already did a rough seating depth test before doing the ladder. but in your opinion do you think another seating depth test is warranted with new possible node before loading and re testing the 87.4 with a chrono and 5 shot groups to verify?

 

[Rifles And More]

I'm not going to be a lot of help - I'd pick the 87.4 specified and do a seating depth run. Then, check it over the chrono. Hopefully, you will see a low ES and SD.

 

[Rifles And More]

Just for reference, I finished the pudding today.

Found my velocity node first - 50 shots
Seating depth test - 21 shots
I'll make one dummy round to set up with in the future.
Load the remaining to verify velocity with a six-shot group, group size with a six-shot group and then run my drops from 300 to 1K

All done at 100yds

Results: the 2.126 is CBTO

 

[Harvey_NW]

Just for reference, I finished the pudding today.

That's some damn fine shooting! Well done.

but in your opinion do you think another seating depth test is warranted with new possible node before loading and re testing the 87.4 with a chrono and 5 shot groups to verify?

Since you already roughed out a seating test I don't think it's warranted until you confirm it's not consistent. I would test 87.4 at the seating depth you used for your ladder. If you achieved your goal, you're ready to validate. If not, continue testing further. I personally try to keep those adjustments small from this point, like .005" increments on seating intervals.

I'm not disagreeing with anyone's preferred method, I just disagree that you can't develop a good load with a conservative approach. Satterlee and many other shooters have proven time and time again that they can shoot 10 shots over a chrono, run a seating depth test, and go win PRS matches. Granted they're usually shooting highly customized precision rifles and sh!t more knowledge than I'll probably ever obtain, I think there's validity.

 

[Rifles And More]

We are on the same page. I'm just using an expanded Saterlee because I'm a numbers geek and need more than the 10 shots to feel comfortable.

 

[Cahunter805]

I would load 87,87.3 and 87.6 and shoot groups at 400 yards to confirm the node. Then you can fine tune seating depth if needs be.

Is this a brand new barrel? If so you might want to just load up some rounds to get the barrel broke in. In my experience most barrels settle in at about 100 rounds and then I fine tune everything after that.