"James Waldby" wrote in message
...
On Mon, 17 May 2010 09:42:41 -0500, Lloyd E. Sponenburgh wrote:
"Pete C." [wrote]:

Yes. It should be a lot easier to setup to weigh each completed round
automatically and alarm on out of tolerance ones, even log all the
weights.

You'll have to tare the weight of the empty casing first. Even minor
variations due to sizing and trimming can affect your total cartridge
weight.

Another weigh (pun) to do this is to measure the mass of the cartridge,
first empty, then with the powder load. A clamping collar at the neck
of the cartridge attached to a piezo-electric transducer can determine
the resonant frequency of the whole assembly with the empty, then
re-tune after filling to determine pretty precisely the mass of powder
added.

It seems like either of those ideas would need an extra station
or two, which Tom wants to avoid using since all the stations of
his five station progressive press already are busy; otherwise he
would use a powder-check die, like he mentioned, and as Stan also
suggested in his post, for some reason, just after quoting Tom's
post that said, "a powder-check die would do just that but I would
not be able to use my bullet feeder or my separate crimp die".

It might be practical to mount an ultrasonic distance transducer
looking down into the cartridge, instead of a webcam. This would
probably be good enough to distinguish no-powder from powder. Of
course accurately knowing how much powder would be a good thing,
but he apparently has loaded thousands of rounds without needing
to measure it for each one, and just wants to make low-powder loads
much less likely.

Measuring the cavity resonance frequency (with a tiny speaker
and microphone) would be another alternative. Of course not
as accurate as the clamp-on piezoelectric transducer Lloyd
suggests, but probably good enough and wouldn't use up a
station.

Would it be practical to weigh each round after it's done? I
don't recall what cartridge Tom is loading, but presumably the
weight difference between powder/no-powder would be a percent
or more (a few grains out of a few hundred), which ought to be
easy to detect, unless the brass varies by that much.
Of course, if the rounds were weighed in the same order that
they come off the press, it would be even more likely that
the "classic sequence" Stan mentioned, a no-charge round
followed by a double-charged round, could be detected.

--
jiw

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.