Help with ladder test

[ballison]

I ran my first ladder test today with a rebarreled 260. I repeated it twice just to confirm everything, and it looks like they were pretty consistent. If I understand how to interpret the results, I'd probably pick #7, which is 43.2 gr H4350. If anyone has experience running and interpreting a ladder test, I'd appreciate your input. Next is to run a similar test keeping the charge the same (43.2) and varying the seating depth to fine tune the groups.

I attached a photo and also a link to a higher resolution pic.


https://drive.google.com/file/d/0BwRL0XOXX8YqOERLMUdWMzBhUjg/view?usp=sharing

 

[timeout]

I can't read the note page very well, but going by the right side target, I would use a charge weight exactly in the middle of shots 9 and 10. This is provided that you do not have any pressure signs with that powder weight charge.

 

[ballison]

I can't read the note page very well, but going by the right side target, I would use a charge weight exactly in the middle of shots 9 and 10. This is provided that you do not have any pressure signs with that powder weight charge.

Thanks for your input. Actually, I didn't notice 9&10. Was looking for 3 consecutive loads, not 2. Worth considering! Actually, 6-10 were separated by less than 2" vertical, so it looks like a pretty wide band. It was a windy day (10-20 mph), so the horizontal isn't great.

The note are the load for each number. Put it there for my info, not so much for the post here.

 

[eric32]

I agree as well 6 - 10 are very tight vertical. I would load in the middle of that

 

[Caleb85]

I'm still kinda new to ladder testing but isn't #1 look good?

 

[savageshooter86]

6-10 look good. I would load #7or #9 and run seating depth test


Once you get great seating depth dialed in you can come back through and re shoot charges 6-10 to see which one shoots the best and narrow down the window

 

[338 Mollett]

You made a good observation.#7 is in the middle of two different tests showing good vertical!

 

[Alex Wheeler]

You will want to shoot another ladder with .1 grain increment in the window you just found. That will show you exactly where to be.

 

[ballison]

I'm still kinda new to ladder testing but isn't #1 look good?

Caleb,
There are a lot of sites that explain how to run a ladder test. Here is the one that I used in my test. It does a good job explaining it and shows actual results.

http://sierrabullets.wordpress.com/2014/07/03/long-range-load-development/

 

[AlanPF]

I like the left side of the target better. Shots 8, 9, and 10 are showing a little positive compensation, which augurs well for further out from 500yds. But that would only be if the velocities were rising, and we seem to be assuming that the loads and velocities are for the holes on the RHS of the target?

 

[timeout]

I agree as well 6 - 10 are very tight vertical. I would load in the middle of that

I agree that 6 thru 10 are very tight for a 500 yard test, however I would be interested in muzzle velocity also as some importance should be put on least amount of time to target.

 

[ballison]

Here are the muzzle velocities for 6-10, avg of 2 shots per charge. ES was much lower for the higher charges, but I would expect this as the case is closer to full capacity. No pressure signs on any of the cases.

# 6 42.9 - 2776, ES=41
# 7 43.2 - 2804, ES=20
# 8 43.5 - 2823, ES=18
# 9 43.8 - 2834, ES=4
#10 44.1 - 2887, ES=0

 

[Judd]

I like between 8 & 9 and especially after you posted the speeds. I'd probably do some experimenting between them.

In the past I would then take that .3 spread and shoot some groups and specifically look for low SD's. But, I am starting to get the opinion that seating depth is more important than powder charge so I'd pick one in that range and mess with seating depth and then come back to that .3 spread. I'd mess with seating depth in .003 differences and one should come together.

Inital testing looks like she will shoot though.

 

[ballison]

I like between 8 & 9 and especially after you posted the speeds. I'd probably do some experimenting between them.

In the past I would then take that .3 spread and shoot some groups and specifically look for low SD's. But, I am starting to get the opinion that seating depth is more important than powder charge so I'd pick one in that range and mess with seating depth and then come back to that .3 spread. I'd mess with seating depth in .003 differences and one should come together.

Inital testing looks like she will shoot though.

Judd,
Thanks for the input. Once the weather breaks here in PA, I'm going to run seating depth tests on 7 and between 8&9. Will post what I find.