Path: utzoo!yunexus!ists!jarvis.csri.toronto.edu!rutgers!att!cbnews!military
From: military@cbnews.ATT.COM (William B. Thacker)
Newsgroups: sci.military
Subject: Re: M16 Ammo
Message-ID: <11498@cbnews.ATT.COM>
Date: 17 Nov 89 06:56:46 GMT
Article-I.D.: cbnews.11498
Organization: Scientific Atlanta, Government Products Div, San Diego, CA
Lines: 26
Approved: military@att.att.com



From: uunet!sagpd1!jharkins (Jim Harkins)
If M16 ammo tumbled in flight it wouldn't be a very accurate round.  As the
rifle is used in shooting matches I tend to assume it keeps its nose forward.
But when it hits the target it tumbles.  Or if it hits a twig, bush, or what
have you it tumbles before it gets to the target (rarely hitting).  But it
was decided by the powers that be that being hit by a bullet that tumbled on
impact was cruel and inhumane.  So the original barrel twist was shortened
from 1:12 to 1:8 (I think).  So there's a new problem.  Now when the bullet
hits it fragments.  So whats worse, being hit by a bullet that tumbles or
by one that fragments once inside your body?  

I remember about 2 years ago I went to the desert with a friend who liked
to reload ammo for his AR-15.  He had a batch of bullets that wouldn't even hit
paper at 100 yds.  Nor at 50 yds.  Nor at 20.  At about 10 we noticed lots of
little holes around the target.  Turns out the bullets were tearing themselves
apart as soon as they left the muzzle, he'd mistakenly bought bullets designed
for the 1:12 twist and was shooting them out of a 1:8 barrel.  Think about it,
1 Revolution every 8 inches, traveling about 3300 fps, is 297,000 RPM.
You physics students, how much rotational energy does the jacket of this
bullet have to contain, considering it's a 55 grain slug? (side note: how
many grains are in an ounce/gram?).

jim
"Happiness is lots of little things.  Green, about 2 1/2 by 6"