Ladder tests for two different powders

[Longshot]

So I've been having some issues with my 6xc in that I can't get it to shoot under .5 moa which I think should be pretty doable. Anyways I have been running 39.5 gr of H4350 which seemed to give me .5 moa but nothing better on a consistant basis. So I got some info off of another shooter on another forum and he kindly sent me his test data which said 8208 XBR was the powder which produced the least amount of vertical.
So I figured what the heck,I have a pound on the shelf,I'll go shoot a ladder to see if it is any good in my gun.
So as a baseline I shot a ladder with H4350 first.
Here it is.

Looks like I actually should have been around the 40 gr mark. There was no sticky bolt at all and only a slight ejector mark on the base of the case.

So then I ran a ladder using 8208 XBR utilizing the data the other chap sent me.
This is it here.

As you can see it ended up putting shots 5,6,and 7 pretty much through the same hole at 200m(as far as my test range allows). And #s 3+4 weren't far off either. I stopped at shot 8 as I got some sticky bolt lift and that,incidentally, was right where the other fellow said things would start to go south.

So next up is to shoot a couple of groups at that powder range of 36-37 grains.
I'll post up the results after I'm done

 

[elkhuntr]

Outstanding work!!!!

 

[Mystic Precision]

http://www.mysticprecision.com/wp/1158/load-tuning-to-maximize-lr-accuracy/

Here is my variation on the theme. I found the 1 shot process open to far too much input error - I screw up and the data is badly corrupted. A bit of wind and the best load could be lost in the noise.

Has served me well and gets me to the right nodes in a big hurry.

You should also add in a chronograph. My SWAG is the H4350 loads aren't high enough in pressure to reach the node the barrel wants. But then you are likely out of case capacity?

The IMR8208 loads started to get sticky bolt lift indicating some toasty pressures. The H4350 loads didn't. 8208 is substantially faster in burn rate then 4350.

My guess is that the speeds of the 8208 would also be higher then the 4350, the pressure certainly is. If this shows more promise, then add in AR Comp and Varget to the mix. I like a case at 100% load density and the 8208 load may leave a bit too much space.

But if the groups work out at LR, have at it.

Jerry

 

[Haagen_Dazs]

Ah yes, the ladder test. I'm learning more and more about all the different adaptations of this test and I'm not saying your test is invalid, but it's not how I would do mine.


It's nice to see your 8208 XBR results show a pattern, but I'm a fan of probability and statistics and from that 1 sting of 8 shots, I think you're only really seeing half the picture. When I did 4 different ladder tests, I shot 3 strings of 8 and next time I do it, I'm going to try 4 strings of 6 (still only 24 shots). This is because 4 shots for each charge weight will give a more accurate MV reading.

Which brings me to my last point; chronographs! After seeing the MV vs charge weight results for my 4 ladder tests, I don't think I'll be so concerned about how the strings patterns downrange. Instead, I'll use the pattern to reinforce the chronograph findings.

You can see how even with 3 shots, there are 1 or 2 velocity nodes that show up in each test! In order to reduce/illiminate all uncertanty, I plan on buying a 2nd chrony and setting them up in series.

Ladder tests are a very useful test for any loader and it's cool to see post like this one!

 

[Lead Loader]

ya id say only doing one shot of each isnt helping, you need to do more to take out anything like a pull or wind and get more accurate data to work from

 

[Longshot]

My next step will be shooting some groups to find out if the 8208 node has promise. I understand what you guys are saying about the data. I just don't want to use up any more of the accurate life of this barrel in testing. The range I test at has little to no wind usually and I am very confident in my ability to break only perfect shots OR call any pulls that may happen. The rifle was bagged in so there wasn't much room for errors.
Jerry perhaps you are right and I should go higher with the H4350. Perhaps if the 8208 groups aren't as promising I will give it another shot.
Sean Clark (Spclark) over at 6mmBr did extensive testing with a whole bunch of powders in his 6xc and sent me the results. So far his testing has been bang on with my rifle as well so I will carry on with it for now.