"Buerste" fired this volley in
:

I mostly load .38 but followed closely by .45 then 9mm.
Unfortunately, my sweet load is 2.7 grains of 700x which is not a
bulky powder and my cast bullets vary by more than that, cases aren't
much better as I use mixed headstamps with questionable pedigree. I
use the .38s in a .357 Smith that would handle a double load. The
auto loaders scare me the most.


Then cavity resonance might not be the best way to measure it, although
it's a good idea if you were working with factory-new brass. Either
weight or mass are the _only_ ways you'll tell if the load is correct.
Also, you'll have to do the final check before you place and swage the
bullet.

It _could_ be reasonable that the same station that did the powder
loading could measure the mass before and after powder loading, but
before the turret turned. The way progressive loaders work, I think it
might be better to make a transducer that impinged on the side of the
case being measured, than to have a transducer per station, with the
requisite problems of connecting them electrically as the turret moved.

There are a number of problems to solve -- elasticity of the clamp that
holds the casing, moving the transducer probe to the casing, a
calibration method that "knows" how loads within the acceptable range
affect the resonant frequency (dropping it, of course), and so on.

LLoyd