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From: consp04@bingsuna.bingsuns.cc.binghamton.edu (Dan Boyd)
Newsgroups: sci.military
Subject: Re: Secondary Armament
Message-ID: <1991Jun18.074449.15112@amd.com>
Date: 14 Jun 91 20:25:03 GMT
References: <1991Jun14.080001.19997@amd.com>
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Organization: State University of New York at Binghamton
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From: consp04@bingsuna.bingsuns.cc.binghamton.edu (Dan Boyd)


When they were designing the M-1, they looked at various kinds of
secondary and coaxial armament.  One member of the team wanted twin
.50 caliber machine guns for the co-axial armament.  They'd be stable
and accurate out to hundreds and hundreds of meters -- but it was
discovered that they wouldn't be much use, since the bullet wouldn't
explode.  They later settled on the 30mm M-25 Bushmaster cannon used on
the Bradley as the best choice for the co-ax weapon.

The commander gets a .50 caliber machine gun, but it's not stabilized
so you can't use it on aircraft unless they're really low.  The loader
gets an M-60 as well, which is a new thing -- the M-60 and the M-48
didn't have guns for the loader.

[That information came from Orr Kelly's 'King of the Killing Zone.]

But production M-1s don't have a 30-mm cannon as their co-ax.  This
wasn't mentioned in the book. They have a 7.62mm machine gun.  That's
right - just an M-60.  Why?

My guess is, anything that you're going to shoot the Bushmaster at is
worth shooting the main gun at.  If it's got a THICK metal skin, you'll
need a sabot or a shaped-charge shell.  If you could damage it with a
30mm armor-piercing round, then why not hit it with a regular HE 115mm
round -- that way, you could get it with a near-miss as well.  The
co-axial armament is for shooting at people with when you're in a
hurry, hence a machine gun.

Suppose we're driving around through the woods with the commander and
loader at their guns.  And someone pops up and sprays the top of the
tank with an assault rifle.  Now the commander and loader are probably
out of action, and the gunner still has the co-axial MG to hose down
the area with.  You can't hose down a row of bushes with a 30mm
cannon.

Also, you've only got to carry three kinds of ammo: Main-gun, .50
caliber, and 7.62mm.

You don't want a minigun or a Vulcan as your co-axial armament either
-- they eat ammo like there's no tomorrow.  Aircraft armament is
designed to throw as much of the ammo as possible out in as little time
as possible -- because the aircraft is cruising by really fast.  If you
didn't use a minigun on the helicopter, the bullet strikes would be
spread out too far.

--
Daniel F. Boyd
consp04@bingvaxu.cc.binghamton.edu