From: [EMAIL PROTECTED]
The author put it down to auto-acceleration, conjecturing
that the very small charges of powder were laying along the
bottom of the case and igniting together instead of in
'sequence' along the case giving a rapidly rising and massive
pressure curve.
Note also that in several of the American reloading manuals
'minimum charges' are stated as well as maximum. I don't
think this is because the bullet wouldn't leave the barrel.
I'm not all that convinced by this "autoacceleration"
malarkey. In the case you relate if *very* small charges of
powder were being used perhaps they just weren't igniting
properly rather than anything else? I remember reading
about this a few years ago and one powder manufacturer
(Vihtavouri?) did loads of tests on this and couldn't find
any evidence for it at all. Smokeless powder is actually
quite difficult to ignite properly, I tried a load with 2400 in
.38 special once and unless you used quite a lot of
powder it just wouldn't work properly, you would get loads
on burned powder dropping out the end of the barrel and
the bullet would embed it's self in the cardboard target
backing, sideways usually. From this is would seem
possible that the flash was simply missing most of the
powder so it wasn't being ignited properly and thus giving
erratic results.
Yes loading manuals do give minimum charges
sometimes, but these I think are mostly to avoid
hangfires. If you look at data for very large rifle cases it
will sometimes tell you not to reduce charges as the
powder will not properly ignite due to the flash from the
primer jumping over it, believe me I've tried to poo-poo
these warnings, you know the thing "Well I'm more
cleaver than this highly trained explosives engineer who
wrote the book, so I'll put light charges in a .460
Weatherby case and just pack 'em down with toilet paper
so the charge dosen't move!" Well guess what folks? The
charge does move and when it does the rifle hangfires
and it's not pleasant even with a much reduced load. I
would hate to think what it would be like with an almost
full load. I used to use a load of 110grns of H414 under a
405 grn bullet, I had to increase that to 112 grns because
of the occasional hangfire.
Jonathan Laws
Cybershooters website: http://www.cybershooters.org
List admin: [EMAIL PROTECTED]
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