The Custodian mentions that the M-16 had some
problems when it was first introduced, but there's
more to it than that.
As designed by Colt, the M-16 was a highly
reliable weapon. But getting it adopted by the
army had much more to do with politics than with
whether the gun actually worked or not.
One of the political problems was that Colt spec'd
the M-16 to use a modern smokeless powder, and the
boys in Army Procurement didn't like that. They'd
always used something called ball powder, which
was manufactured by a company just down the road, and
they didn't see any reason why their buddies
should lose the bid'ness on account of this
new-fangled M-16 weapon.
So they took the M-16 and put it through its
paces, looking for any excuse to disqualify it.
And they found one. Seems that Mil Specs called
for a muzzle velocity of 3000 ft/s across the
entire temperature range of -30C to whatever, and
if you took the rifle to Alaska and fired it at
-30C ambient, the muzzle velocity was only 2950
ft/s, and there you go: it doesn't qualify.
BUT, they also discovered that if you used ball
powder, the muzzle velocity meets spec at -30C.
Problem solved.
Except for the other problem, which is that the
weapon didn't work at all with ball powder. There
were actually two problems. The first was the
limestone build-up described above.
The second problem was the firing rate. The firing
rate is a basic design parameter of an automatic
weapon. As designed by Colt, the firing rate of
the M-16 was around 800 rounds/minute.
Ball powder produces a higher chamber pressure
than the powder that Colt recommended. Chamber
pressure matters, because that's what drives the
repeating mechanism of the gun. With ball powder,
the M-16 fires at over 1000 rounds/minute; or,
more to the point, it jams at over
1000 rounds/minute.
When the gun fires, there are parts that have to
move: springs, levers, the bolt, the spent
cartridge, the fresh cartridge; and at 1000
rounds/minute, these things just don't happen in
time. So the weapon jams.
Colt tried to qualify the M-16 with ball powder,
and found these problems, and told the Army in
writing that the gun did not work with ball powder.
The Army wrote back that
they didn't think that the problems with the M-16
had anything to do with the powder, and that Colt
could qualify the weapon with any powder they
liked.
So Colt qualified the M-16 with the powder that it
was designed for, the Army sent the M-16 to
Vietnam with ball powder, the guns jammed, and
soldiers died. Soldiers who didn't die wrote home
to their parents, and parents wrote to
congressmen, and eventually there were
congressional hearings.
The hearings were a good illustration of the ultimate banality of evil.
Here was a
very bad situation: incompetence;
malfeasance; corruption; lots of body bags. And
when the Congress of the United States tried to
find out what happened and why, all they got were
these petty bureaucrats testifying that, yes, when
fired with the manufacturer's recommended powder,
the M-16 muzzle velocity at -30C is...
The Army never did back down on its commitment to
ball powder. They reduced the calcium content in
the powder to prevent limestone formation, and
they changed the stiffness of a spring in the
M-16 to bring the firing rate back down to 800
rounds/minute, and they went on from there.