With nodes mostly repeating approx 3% apart , anti nodes seem to as well, so not only am I looking to identify a decent node to work seating depths I’m also looking to stay away from the more unstable anti node. On the target below I’m in a stable spot at 31. 4 - 31.6 but 31.7 through 32.0 is kinda no man’s land so I don’t think I would trust any seating data from that charge rate.
Question;
So if we just find pressure ( at 32.4 ) how far would you back of to start your seating depth testing ?
Jim
Much like what you're saying here
Within the ladder (Say 10 shots)
I look for stable AND note erratic behavior in the shot placement
As well as velocity
For instance I remember working a ladder going from 49.0 grns up to 52.0 grns
at 51.0 shot placement was Spot on, exact
at 51.5 Velocity did not increase much, maybe 12 fps
So I held at 51.0 grns because POI to POA was more consistent and proceeded to keep testing at 51.0 for consistency.
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That's the load I used to shoot the pictured group (And many others like it, this is just the first time the load confirmed its consistency )
first it was a 3 shot
then came back later and reset up
and put another round right into the same group pictured
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I notice some guys here are saying they also look for POI relative to POA withing their load development
I know sometimes when going up the ladder shots may start printing right or up etc.
and guys like me say - Just re adjust your scope
But I think what they're saying is what I am doing without thinking it....
I want to see.....................that my shots keep producing the same
POA=POI ( during the ladder even though we CAN adjust the scope to compensate if it migrates out)
I don't adjust the scope yet because I want to see how far away from POA the shots migrate as I work up the ladder.
So when all shots POA =POI
Whether I setup here or down the road or at another range etc.
if the shots seem to naturally go to POA
Almost without trying, as if the bullet hones in on your POA,
.... I migrate to the charge that produces those results
even if it is 12 fps slower lol or (even if it is 50 fps slower)
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Good point on the Anti-Nodes
because some of us may want more velocity and simply adding more powder isn't the right way if we bring the load into an Anti-node
So how far would I back off once reaching pressure you asked?
I would back off to the last charge weight that was putting rounds into consistent POA's
Or where POA equaled the most consistent POI's
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Another quick and dirty way to run a ladder I have done is
Shoot a 10 shot group at one POA
This would be similar to the waterline test, except you're keeping the same POA instead of each shot being a new POA.
Watch where all those shots go
1st and 2nd may be 1/4" away and then there will be 3 or 4 shots you will see going right into the same hole
then the rest will start to migrate out again.
Now work the load with those 3 or 4 shots that went into the same hole and fine hone the load
this is just if I am trying to get a buddy's or my gun to shoot within 1/2" real quick maybe for a hunt or varmint shoot or something, its quick and easy
I've developed a lot of loads for other people and got tired of having to shoot 100 rounds or more or repeated trips to the range as if Im developing a benchrest load, when it wasn't really necessary.
So this method could also be used to find a good starting point to fine tune any load really.