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.