Help with load development and interpretation of results

[turbo_bird]

So to begin with, I'm relatively new to trying to work up a good accurate load for a rifle. Most of my reloading has been for pistols, coming up with something that is safe and feeds reliably, as well as making the required power factor for IPSC. The rifle I'm loading for is a Carl Gustaf 3000 that I bought from Tradex last year, in 6.5x55. I'm using Lapua brass, once fired and neck sized with a Redding die, Barnes 145gn Match boat tail bullet, and Reloder 22 powder. I loaded 3 round each in .2 grain increments, and fired groups at 200m. I let the rifle cool down to somewhat warm between groups, and the wind was changing throughout the day. It was mostly cloudy and somewhere around 20 - 25 C. I forgot to bring my chronograph, so don't know the velocities, but the elevation changes don't seem very big or very consistent between the various charges. I was thinking about doing a typical ladder test, but thought 3 rounds at each charge would allow me to eliminate fliers and reduce the effects of shooter error, but it looks more like I just can't shoot good enough to get meaningful results. The grid on the target is 15mm, and the graph paper is normal 1/4".

I've got my results so far marked up on a single target, and am looking for some help with figuring out what I'm doing and what I should be looking for.

This is my colour legend for which shots go with each powder charge.

On this page I've marked just the elevation of each shot, relative to each other.

And my best group, just because. This one was loaded with 43.8 gn.

I graphed out my averages and also threw out what looked like the most obvious fliers, to meet it looks like I should concentrate on the 44.2 to 44.6 grain area. I also have more rounds loaded to try up to 47.2, but ran out of time to shoot them.

I'm almost thinking my results just mean I need to work on my shooting consistency, but if anyone has any thoughts on what I've got so far, I'd love to hear it.
Kristian

 

[adamg]

Another day, another post that substantiates my claim that ladder testing is not a legitimate load development technique. My claim is that the noise is much larger than the signal, so no conclusion about 'optimum' anything can be drawn from the data.

 

[South Pender]

Turbo_bird, I'm sure you're aware that your CG3000 has a Sauer 80 action, and this means rear locking lugs. This will limit your handloading somewhat as case stretching will occur (true with any rear-locking action). If you shoot near-maximum loads, full-length resizing will result in very short brass life--maybe 2 or 3 reloadings. Lighter charges will extend the brass life a little, but not all that much. I'm wondering whether your 46-gr. loads might be near max.

 

[turbo_bird]

Turbo_bird, I'm sure you're aware that your CG3000 has a Sauer 80 action, and this means rear locking lugs. This will limit your handloading somewhat as case stretching will occur (true with any rear-locking action). If you shoot near-maximum loads, full-length resizing will result in very short brass life--maybe 2 or 3 reloadings. Lighter charges will extend the brass life a little, but not all that much. I'm wondering whether your 46-gr. loads might be near max.

Thanks. Yes, I'm hoping to find an accurate load that will give me decent brass life, as well as neck sizing to hopefully extend it some more. I've got several rifles chambered in 6.5, but it's easy enough to keep the brass separate for each one, and I've got 300 pieces of Lapua brass set aside for this one.
Kristian