Bullet depth vs powder charge, which first?

[garandman]

You skipped seating testing. This thread is about when to DO seating testing.

No. I did not skip anything.

You need to re-read my first post. Apparently you skipped reading and went straight to assuming / arguing.

 

[garandman]

never change more than 1 variable at a time in when testing or it impossible to know which variable you changed contributed to a change in the test results

This SHOULD be obvious...

You'd think...

 

[garandman]

This is my understanding of why you find the right powder charge 1st and 2ndarily work on seating depth....

The way it was es'splained to me... The powder charge determines the velocity of the bullet in relation to the harmonics of the barrel. The right velocity bullet will sync well with the barrel harmonics to produce a consistent pattern down range. Barrels essentially move in a sine wave pattern when the round is fired. The wrong velocity bullet will fight agains thte bbls inherent sine wave... And open your group's up at distance. There is probably a better way to explain that, but that's the gist of.

Once you have found your load then you fine tune with seating depth. I've tried this. It works.

 

[JimSC]

here is a rough load workup I did a few months back. I experimented with finding seating depth first then fine tuning the powder charge for the lowest SD/ES. These were shot when the barrel had less than 100 rounds on it and the temps were 50 degrees cooler. I have not had a chance to play with the load this summer but I would like to get that ES/SD down a bit lower and do some fine tuning. I hope to get to that in the next couple of weeks.

All loads were loaded at home and weights were measured to plus or minus 2 milligrams. The first 5 rounds were used to check for pressure signs and ranged from 37.5 up to 39.5 grains. The next 25 was a seating test using 38.5 gns of powder. I started with rounds at .109 off and worked my way down to a soft seat into the lands.

Then I followed with testing charge weights. The targets were scanned and measured in OnTarget then all results put in a spreadsheet. I also attached a practice target from 300 yards. Nothing spectacular and way off center but that is the indian's fault not the arrow's

 

[TrxR]

Will seating jammed into the lands cause higher pressure needing a lower powder charge?

 

[Lone Hunter]

I like Berger’s way of thinking. Works for me

 

[mikecr]

There is nothing fine about actual/full seating testing, as it opens and closes grouping by up to 2-3x that of powder adjustments. And don't mistake seating as 'tuning'. See it as a precondition.
That group shaping which manifests with minor tweaking of seating at a powder node, this is still homing in on better seating, -or taken far enough to collapse your powder node as a side effect.

You tune with your load(bullet, powder, tension), and you might as well do this at or at least near optimum seating(as actually tested).

 

[memilanuk]

never change more than 1 variable at a time in when testing or it impossible to know which variable you changed contributed to a change in the test results

This SHOULD be obvious...

You'd think...

Might want to *re-think* that...

DOE vs OFAT (among, many, many examples).

TBH, I'm mainly stirring the pot here. Intellectually, yes, I think that DOE *should* be a better method. I don't think anyone here disputes that powder charge and seating depth both affect the outcome(s) that we are interested in - or that they interact to some degree. By definition then, OFAT is a sub-optimal approach. But, like the use of 'extreme spread' vs. standard deviation, it's much simpler to implement and evaluate 'in the field' (i.e. at the range), usually *without* any math above a 3rd grade level - and nobody's arguing the results, which in the end, are what matter most.

BTW, the 'Boyer' method is basically a full factorial experiment across two factors (variables), with an arbitrary number of levels (# of increments of charge weights, and of seating depth). Some might argue that it's not the most *efficient* approach, but for our application here, over a limited range and for only two variables, it's efficient *enough* - and as already mentioned, it gets the job done.

 

[garandman]

There is nothing fine about actual/full seating testing, as it opens and closes grouping by up to 2-3x that of powder adjustments. And don't mistake seating as 'tuning'. See it as a precondition.
That group shaping which manifests with minor tweaking of seating at a powder node, this is still homing in on better seating, -or taken far enough to collapse your powder node as a side effect.

You tune with your load(bullet, powder, tension), and you might as well do this at or at least near optimum seating(as actually tested).

My way works for me.

 

[Texas10]

It's been my operating theory that everything we do the "fine tune" a load is all about barrel time and getting the bullet to leave the muzzle while the harmonic reflection is nearest to the chamber end of the barrel.

To that end, charges vary exit time in large steps, and bullet seating varies it in small steps, and the target tells you which way the muzzle is pointing when the bullet exits, presuming the shooter can execute the shot consistently. (HA!, I know that's the biggest hurtle for me)

So I start with the bullet seated either .010 in the lands or .020 out and work the charge, then adjust the seat, then neck tension, then primer, then consider purchasing a(nother) new barrel...LOL

 

[garandman]

It's been my operating theory that everything we do the "fine tune" a load is all about barrel time and getting the bullet to leave the muzzle while the harmonic reflection is nearest to the chamber end of the barrel.

To that end, charges vary exit time in large steps, and bullet seating varies it in small steps, and the target tells you which way the muzzle is pointing when the bullet exits, presuming the shooter can execute the shot consistently. (HA!, I know that's the biggest hurtle for me)

So I start with the bullet seated either .010 in the lands or .020 out and work the charge, then adjust the seat, then neck tension, then primer, then consider purchasing a(nother) new barrel...LOL

EXACTLY my real world experience and theoretical understanding.

 

[garandman]

In reality… since each barrel is going to have one particular charge weight and 1 particular seating depth that it likes best, it probably really doesn't matter which 1 you do 1st.

 

[Tim Singleton]

Sometimes I think it would be nice to know how successful those are that give their advise on topics like this
I mean real world match statistics

 

[Sixgun]

Will seating jammed into the lands cause higher pressure needing a lower powder charge?

Yes.

 

[garandman]

TBH, I'm mainly stirring the pot here.

Well... at least you admit it.

 

[garandman]

Sometimes I think it would be nice to know how successful those are that give their advise on topics like this
I mean real world match statistics

Indeed.

My way works *for me.*

Ive got the targets to prove it.

I wont even bother trying to prove other ppls methods dont work for them.

And for reasons I already explained, it actually probably doesn't even matter whether you start with seating depth or whether you start with charge weight as long as you eventually do both completely.... ...

 

[mikecr]

When you calibrate dynamic things, say a 4 barrel carburetor, or analog process control, etc., you eventually gain an understanding of order. That best is wherever it is, BUT, there is an easy path to find it, or a difficult path, or an unlikely path (luck).
I don't believe it all works out the same.