A few bits and pieces:
The 20mm gatling used by the USAF can still go through a large fraction its
barrel life (half?) in one burst. The longer the burst the greater the wear. I
imagine they use quite Âhot loads in it to make up for its small calibre
(20mm) and the lag as it takes time to spin up. Apparently they were going to
move to a larger calibre weapon about thirty years ago but have not changed
yet.
There is footage of a Russian ship mounted AA gun being cooled down after
firing by a sailor plying it with a hose.
A Shortage of brass was becoming a major concern for the Germans in WW II in
part because almost all of their artillery used a brass case to seal the
breech. They devolved steel cases for small arms and less successfully for
artillery and were trying to develop breeches that would seal with bagged
charges, I wonder why they did not just copy captured weapons though, mind you
this was Nazi Germany so logic seems to go out of the window.
I read in one of CapstickÂs books (Maneaters I think) about a hunter in
Africa who defended his camp against cannibal attack with a shotgun, he fired
it so rapidly the solder holding the barrels together began to meltÂ
A few years back they carefully measured a Vickers and then fired it all day
and measured it again. They were no signs of increased wear on her at all.
I believe the M60 in Vietnam could Ârun away if it became too hot, the hot
chamber cooking off rounds in the breech.
> The 20mm gatling used by the USAF can still go through
The AirForce version of the JSF is supposed be armed with a 25mm gatling
internal gattling. There's a 25mm gattling pod for the other version of the
JSF.
> A Shortage of brass was becoming a major concern for
Steal cases tend to jam much more often then brass. This especially true in
weapons that get very hot, ie., machine guns and artillary that's being fired
a lot.
> I believe the M60 in Vietnam could 'run away' if it
The M60 fires from an open bolt. This means that the round is only in the
breach for a fraction of a second before it was fired. I suspect the "run
away" problem had much more to do with: 1. Faulty ammunition that did not
generate enough pressure to fully cycle the weapon. 2. Defective parts in the
weapon. 3. Or mostly likely, the weapon had been fired a lot before it's last
cleaning, and powder residue reduced the gas flow to the piston, thereby
preventing the weapon from fully cycling.
The M-60 problem was due to cook-offs (firing due to heat).
Michael Brown
[quoted original message omitted]
> At 6:19 PM -0800 3/12/03, Michael Brown wrote:
Well, there was also that small stupid design where the bi-pod was
part of the barrel and not the gas tube/receiver. Also, not having a
nice easy to handle handle on the barrel when you remove it is a bit of a
screw up.
> Well, there was also that small stupid design where the bi-pod was
Let's just say that the M60 was such a "good" design, that the U.S. Army Tank
Command (probably wrong name, but the part of the Army over tanks) rejected
the M60 for coaxial use and went with the FN MAG instead back in the 1960's...
> The M-60 problem was due to cook-offs (firing due to heat).
Somehow, I really doubt that the M60 was cooking off with the bullet no where
near the chamber. The temprature required to cook off a round in the fraction
of a second that it is in the chamber before primer ingnition would have to be
hot enough to melt steel.
The probably result of the run away firing is that the gas piston was getting
enough pressure to fully cycle the weapon. This means although enough energy
was being transmitted to eject and ready the next round, but there was not
enough to push the bolt carrier a few hundereths of an inch farther back to
engage the sear the prevents run away.