| From: | Paul J. Adam Paul@********.demon.co.uk |
|---|---|
| Subject: | Ballistics (was: Two firearms at once) |
| Date: | Mon, 8 Mar 1999 23:13:37 +0000 |
<acgetchell@*******.edu> writes
>As a practical note, regardless of initial velocity all bullets tend to
>drop into the subsonic regime by around 900 meters, which degrades accuracy
>at that point. Not saying it can't be done, but I would tend to think
>sceptically of snipers making kills beyond that range.
Just to nitpick, a few calibres remain usable for sniping past that
point: all are large, powerful specialist rounds, chambered in hefty
bolt-action rifles with semi-automatics very rare.
The best example offhand is .338 Lapua, which doesn't drop into
transonic instability until ~1400 metres or so. No idea when .50BMG goes
subsonic :)
For machine guns, of course, you either watch the tracers, or if the
tracers have burned out you look for strikes. We trained on the basis
that a tripod-mounted GPMG(SF) could be effective out to 1800 metres, if
you could observe the fall of shot and adjust it onto the target area.
Of course that wasn't for shooting at individuals, but for area fire.
>It would seem be one
>reason why the OICW went for a bursting area-munition to achieve their .3 -
>.5 hit probability at 1000 meters.
The only way you'd _ever_ achieve it with an infantryman's weapon... and
a pointless requirement, since when was the last time you ever expected
to _see_ a camouflaged infantryman at more than a few hundred metres?
'Tis a nice concept, but I'm unsure how useful it will be: shades of
SPIW and OICW, over which the simple, reliable, cheap and trusted M16
triumphed.
>P.S. Note to Paul: I did mention that diameter of the round (i.e. wound
>channel) is also important in determining volume of tissue damage. Body
>tissues are elastic, and there is a minimum amount of energy that needs to
>be imparted to cause trauma. Small, hard (compared to the body),
>fast-moving pointy objects are rather good at doing so.
And long spun projectiles, nutating their way through tissue like blunt
Cuisinart blades, are also much more efficient at causing incapacitating
injury than short relatively stable pistol bullets: hence the claimed
effectiveness of FN's 5.7mm round, which has a small but energy-dense
bullet to pierce armour, but a long spitzer bullet to cause severe
wounding.
--
Paul J. Adam
