More ladder testing questions ( chasing seating vs powder)

[eric n]

Hi all.
I have a few questions regarding a recent ladder and was hoping for some insight or advice from those more experienced. I usually shoot prone so I do ocw type development because of human factor so my experience is limited with ladders.
6 dasher .155 freebore.
105 vld .10k in the lands (past touch) for powder test.
31-34.5g varget shot at 545yds.
Gun was to be used for 300-600 yd fclass but I'm doubtful this barrel will see a match so it will be used for fun br type stuff.
The powder flat spot was clearly evident and I settled on 33.5 @3050 fps for seating testing.
On to seating...
Seating was done in .003 increments from .015 out to .013 in at 220yds.
From .003 to .013 in the lands (past touch), there is a very small but accurate node. From .003 to .015 out, there is a wide node from .003 off to .009 off that showed vertical stringing with no horizontal dispersion and appeared to have very good wind resistance.
Should I redo a powder ladder seated in the middle of the wider seating node off the lands?
Does 220 yds give valid results for seating?
Or should I load the .009 in the lands, chase erosion and call it good?

Ignore that +6 on the bottom. I goofed up my seating and didn't have anymore rounds loaded long.
Thanks for any advice, its much appreciated.

 

[dmoran]

I suggest to just fine tune the powder, to pin point the dead center of the node.
Not only finding the center, but also the size of the node.
Like say its size is from 33.4 to 33.7 = center 33.55
(with a velocity size of say 3035-fps to 3060)

Is how I would proceed
Donovan

 

[C. Collins]

Use the ladder test to give you a ballpark. Then with the results of the ladder test begin shooting with a chronograph. You are only adjusting charge weight. Seating depth will remain the same. Look for low teens single digit sd. When you find a charge weight then begin adjusting seating depth. I hope this helps

 

[jdj71]

eric, look on pp.48 of this forum for dmoran's "ladder testing" a better " how to" you will not find it is clear, concise, factual. Thank you Donovan.