"Buerste" wrote in
:


"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.

I have had a squib in 223, but the neck was tight enough that the bullet
stayed put (thank goodness). With rifle cartridges, the powder charge is
big enough that an empty is easy to find by weight. In addition to
adding an extra inspection step, I can weigh small sets of cartridges &
tell if anything is amiss.

I've got a new Dillon 650 press with a powder level checker. I will feel
much better once I get that up & running.

Doug White