Ladder Test@600 yards Input

[savageshooter86]

So tried a 3 shot ladder test at 600 yards. 3 shots each charge weight shot all in row under near same conditions. Kinda like the BR guys do I think. 6 charges. I also did same ladder with same charges but tried a different primer. Also had my Labradar going to get more data all at once

thoughts on results?

 

[savageshooter86]

Second ladder. Different primer. Same charges

 

[RegionRat]

Your total shotfall patterns look very good for 600 yards, so you are in great shape. I find that when the whole ladder test fits inside the 9 ring there is nothing to cry about. Some guns go from the 5 to the 5 with a 3 grain spread.

The KV7 looks like a search near 51 for charge and seating depth may do well. And I’m not sure why your Fed testing had the third string climb up out of family, but the middle of the test range should also be tried for groups with seating depths.

A finer Charge Weight search near the middle of these spreads to see where your SD shrinks and then play with jump is where I would go next.

Also, it is easier to study the verticals if you open the file and plot the Y dimension for those shots against charge weight on one plot, and velocity on another. You will see where the plots neck down.

 

[D-4297]

After looking at your charts , my biggest question would be :
How did the three shot "groups" compare , with the data ? Regardless of numerical data , grouping is , or should be more important than numbers , unless the numbers relate to a score that's shot . When I shoot ladders , my focus is primarily on which load shoots the best group on a consistent basis . One of those loads shot a workable group that was better than the rest .

 

[savageshooter86]

Yeah I got the X/Y data in each charge. But didn’t want to confuse anyone on here

thanks for the info above

 

[David Christian]

Did you fire a few blow off rounds before starting the test? If so, is 50.5 covered by shots 1-3, then 50.8 is 4-6, or did you round robin your shots? Also, how did you decide to start at 50.5? Looking at the speed increases, your node might be just below your current starting point.

If those were my results I would repeat the test (round robin charge weights) starting at 49.8 and only go up in .2 grain increments and stop at 50.8. The tighter charge increments should show you the start and stop of your node.

 

[tom]

I like the 210s myself. Around 51.0 would look to stay solid. The 1,2,3 "group is the only bad group on the 210 primer, with the number 1 being the outlier of that only poorer group. The kv7 threw in a couple poor vertical groups. Primer choice for me has been whichever one will shoot a group even when there's a shift in the load/weather. Assuming you're gonna want to shoot some 1,000 as well, building in forgiveness is never a bad idea. A simple bullet B.C. spread large enough to cause a half inch of vertical at 600 is enough to be a mid 3s shift at 1,000....znd that's assuming it was on track to be a zero! Whole different game, so forgiveness is GOOD.

Tom

 

[savageshooter86]

Did you fire a few blow off rounds before starting the test? If so, is 50.5 covered by shots 1-3, then 50.8 is 4-6, or did you round robin your shots? Also, how did you decide to start at 50.5? Looking at the speed increases, your node might be just below your current starting point.

If those were my results I would repeat the test (round robin charge weights) starting at 49.8 and only go up in .2 grain increments and stop at 50.8. The tighter charge increments should show you the start and stop of your node.

@David Christian
Yes 1-3 are 50.5. 4-6 50.8. I fired each powder charge at same POA as quick as I could with as good of technique as I could Then let barrel cool and then repeated same test with different primer. I fired 8 blow off shots prior to shooting the first ladder

50.5 as my last few barrels were around 51.4. Seating I chose because seems all my barrels like that area as I have my own reamer. Usually 18-27 jump shoot nice

thanks for your input

 

[savageshooter86]

Thanks Tom. First time attempting a 3 shot per charge or seating ladder. It will be 1000 yard rifle as well as 600 yards. So next I would test seating in fine increments shooting 3 shot groups just like this ? Or fine tune powder before seating? Trying to do similar to y’all LR accomplished BR guys do

 

[tom]

Thanks Tom. First time attempting a 3 shot per charge or seating ladder. It will be 1000 yard rifle as well as 600 yards. So next I would test seating in fine increments shooting 3 shot groups just like this ? Or fine tune powder before seating? Trying to do similar to y’all LR accomplished BR guys do

With new barrel i find rough seating, rough powder with different primers like you did here. Fine (ish) seating (would use 51.0 in this case) with 3 each if you need to cover ground. At some point i do like to still shoot 5 shot groups when i come back to fine tuning the seating, after the fine tuning of the powder.

Tom

 

[savageshooter86]

So do you shoot round robin or shoot the group for each then move to next one?Shooting round robin one shot each then coming back through and repeating two more times. Then analyzing the three shot “groups” they formed. Guess practice shooting fast like BR guys is key. Shooting round robin through three sets to see groups form seems like a task as conditions can change

 

[David Christian]

@savageshooter86 , when testing at distance 600 or 1,000 I shoot them round robin keeping same POA and then only measure vertical spread on target. Round robin helps with smoothing out any difference in barrel heat between the first and last shot as well as any bias I may form while shooting any one specific group.

 

[Zero333]

51.7 - (13, 14, 15)

 

[SPQR70AD]

can somebody explain to me what a ladder test is? I am not being sarcastic just don't understand it

 

[eric32]

a ladder test is done at distance of 600 yards usually this is where velocity is king and BC hasn't taken over yet.

rounds are loaded at a incremental charge weight
fire at the SAME aim point
then the target shows what powder charge window has the lease amount of vertical dispersion


It is important to know that you must be a consistent shooter to accomplished this test, your results will not be valuable if you cant shoot consistently during this test.

 

[Zero333]

can somebody explain to me what a ladder test is? I am not being sarcastic just don't understand it

A real ladder test is actually what is called "Audette" ladder test. When testing group sizes, that's what most consider an OCW (Optimal Charge Weight) test.

Audette ladder test is shot between 300 and 600 yards (closer than 300 doesn't work). 1 shot each charge weight at the same target/aim point. Then try to find a cluster of consecutive charge weights that group together.

Here is an example I did with a 243win, 107smk., at 330 yards. I settled on #8 (43gr H-4831sc)...

Click on image to enlarge

 

[savageshooter86]

51.7 - (13, 14, 15)

I’m scared it won’t hold. 52.0(16,17,18) and 51.4(10,11,12) POI were off compared to 51.7. 51.7 tempting for some. But don’t think it’s where it needs to be

 

[savageshooter86]

@savageshooter86 , when testing at distance 600 or 1,000 I shoot them round robin keeping same POA and then only measure vertical spread on target. Round robin helps with smoothing out any difference in barrel heat between the first and last shot as well as any bias I may form while shooting any one specific group.

thank you. I recall my first 284 barrel hammered. And working loads up at 600 I only looked at vertical spread. It shot well. Never really worried about horizontal. But I shot 5 shot groups testing.
I will try rd robin at 1000 once I get seating area dialed in some roughly. I’ll be able to test at 1000 next and load at the range.

 

[Zero333]

I’m scared it won’t hold. 52.0(16,17,18) and 51.4(10,11,12) POI were off compared to 51.7. 51.7 tempting for some. But don’t think it’s where it needs to be

In that case, I'll change my opinion to 50.8 (4-5-6).

 

[SPQR70AD]

A real ladder test is actually what is called "Audette" ladder test. When testing group sizes, that's what most consider an OCW (Optimal Charge Weight) test.

Audette ladder test is shot between 300 and 600 yards (closer than 300 doesn't work). 1 shot each charge weight at the same target/aim point. Then try to find a cluster of consecutive charge weights that group together.

Here is an example I did with a 243win, 107smk., at 330 yards. I settled on #8 (43gr H-4831sc)...

Click on image to enlarge
View attachment 1179322

thanks for your answer. I just could not get where firing one shot with a charge of powder then another shot with higher weight of powder could prove. I figured firing a group with same charge would be right but now I understand it