Message no. 1

From:	Richard M Conroy <Richard_M_Conroy@***.ir.intel.com>
Subject:	Re: Ballistics (was Re: Funky Combinations)
Date:	Wed, 21 Aug 96 10:59:00 PDT

:>Tumble rounds DO start to tumble in flight.

But only by about 1-3 degrees off the direction of flight. Forget any
daft ideas of end-over-end tumbling.

:If you mean M-16 rounds, even the marginally stable M193 ball had to
:encounter *something* to make it tumble.

:Once a round becomes unstable, it loses velocity and accuracy almost
:instantly. This from artillery: an underspun shell will *never* be
:consistent ('underspun' means its spin slows slowly and the shell
:begins to tumble as it flies)

:Outside very marginal rounds like .25ACP, nothing I've heard of tumbles
:in flight unless it had previously encountered an obstacle (even a
:minor one like underbrush).

The natural method of flight for long, pointed assault rifle rounds is
to fly end-first (it's the heaviest part). This causes the noted
tumbling effect. An analysis of bullet wounds shows that practically all
the entry holes are round, implying that they entered straight. If they
were tumbling, the wounds would be oblong.

Richard.
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