Round Robin Question

[Aaron Agee]

I'm shooting a 300 WSM Ridgeline and I'm trying RL17 with LRX 175's. I seated the bullets so they were .05 off the lands. I did a round robin session today at the range and got results that I cannot figure out. I have used round robin with several other powders and bullets and was able to find the median result and find a good standard for the powder and bullet. I attached an image with the "mapping" of the groups. Each dot represents each three shot group average and each dot is labeled with the powder charge. I know not to pay much attention to group size when doing RR but the two circled numbers are 3/4" groups... the other groups are 1 - 1 1/2" groups. If anyone can give me insight on these groups please help. My brain cannot calculate! Thanks in advance if you have insight.

 

[ShtrRdy]

I like to consider where the groups are ending up. So if you have two or three groups that are in tge same area pick the one in tge middle. If you want to get a little better group size do a seating depth test.

I noticed you're using 1 gr increments. You may want to try 0.5 gr step size.

 

[WildRose]

I'm shooting a 300 WSM Ridgeline and I'm trying RL17 with LRX 175's. I seated the bullets so they were .05 off the lands. I did a round robin session today at the range and got results that I cannot figure out. I have used round robin with several other powders and bullets and was able to find the median result and find a good standard for the powder and bullet. I attached an image with the "mapping" of the groups. Each dot represents each three shot group average and each dot is labeled with the powder charge. I know not to pay much attention to group size when doing RR but the two circled numbers are 3/4" groups... the other groups are 1 - 1 1/2" groups. If anyone can give me insight on these groups please help. My brain cannot calculate! Thanks in advance if you have insight.

There's no reason to load the LRX so close to the lands and you'll get more consistent velocity with lower pressure by backing it off some.

The results do seem strange but you're changing your barrel harmonics with each different load.

Try a three shot group with any of them and see what kind of group you get. I'm suspicious something may not be torqued correctly or there's a free float issue but with so many different loads it's hard to even guess.

 

[Aaron Agee]

The uploaded image is a mapping of the average of three shot groups (OCW method of load development). Each dot represents the average of a three shot group. The image is not individual shots. The barnes website recommends seating these bullets .050″ off the lands {rifling} of your rifle. I'll load more rounds using 1/2 grain increments and see what happens to the mapping.

 

[ShtrRdy]

When you fire the next round of test loads please post the individual groups with as many in one picture as possible.

What method of resting your rifle are you using during test fire?

Good luck!

 

[Aaron Agee]

When you fire the next round of test loads please post the individual groups with as many in one picture as possible.

What method of resting your rifle are you using during test fire?

Good luck!

I'm using a bipod and sand bag. The three shot groups are all good... two groups under 1 inch and the rest under 1 1/4 inch. I just have never had round robin results like this one and I didn't know what to think.

 

[Deputy819]

I agree with ShtrRdy and would like/need to see individual groups. I sometimes utilize a "modified" version of the OCW method to show me the powder charges that will have the same relative POI on the target. What I don't like about the typical OCW method is shooting it in round-robin sequence which forces you to shoot a different target each shot thereby changing your sight-picture, cheek-weld, how your rifle sits in the bags/ bi-pod position, etc.

 

[WildRose]

The uploaded image is a mapping of the average of three shot groups (OCW method of load development). Each dot represents the average of a three shot group. The image is not individual shots. The barnes website recommends seating these bullets .050″ off the lands {rifling} of your rifle. I'll load more rounds using 1/2 grain increments and see what happens to the mapping.

Ahh. I misread, I thought you were at .005". If you wanted you've actually got room to go forward.

This is not the conventional wisdom but it works very well for me.

Pick one or two of the loads you are happiest with now, try to fine tune them a bit more and then just adjust your seating depth a few thousandths at a time in each direction and see how much more it will tighten up for you.

I find this saves me a whole lot of aggravation, time, and frustration and I get to where I need want to be much more quickly.

For the most part I just load everything to a comfortable mag length, find my best load, then tweak the seating depth for the final fine tuning.

 

[FURMAN]

I see zero usable data in your pic. We need to see groups and need know the distance(maybe I missed it). If those were shot at 100 yards I would not waste anymore time with that powder/bullet combo. The avg point of impact is too far apart.

 

[WildRose]

I see zero usable data in your pic. We need to see groups and need know the distance(maybe I missed it). If those were shot at 100 yards I would not waste anymore time with that powder/bullet combo. The avg point of impact is too far apart.

If I'm reading it right each point plotted is an average 3 shot group and each of the groups is a full grain difference. That's going to throw a huge amount of variation in the barrel harmonics.

 

[FURMAN]

If I'm reading it right each point plotted is an average 3 shot group and each of the groups is a full grain difference. That's going to throw a huge amount of variation in the barrel harmonics.

I do not have near as much experience with the OCW(which is what I believe he is actually trying to do) as I do ladders but the ones I have done I have not seen that much poi change across a grain of powder when the load is good. I personally would do .5 or even .3 grain increments but would expect to see something usable over 1 grain. I would expect a good stable load to have a very small poi change between at least two of those groups. Obviously the group size would change. I have done the OCW with a known good load found with a ladder a couple of times and the avg poi does not really change just the group size. Obviously he can do what he wants but if my rifle/bullet/powder put that on a target in front of me I would move on. On a few OCWs I have done the groups were absolutely horrible but the poi was very consistent. That is something I can work with. All it needed was seating depth test with the center weight powder charge and I had a great, repeatably, long range load.