I am not sure “quench” is the right description. I think in this example the barrel is just being cooled.
In metal working quenching is mostly done to harden steel, changing its microstructure by turning Pearlite into Martensite.
Most common steels need to be heated to around 1,500 °F. I use a magnet to tell when the steel has reached the Curie temperature or Curie point. At that temperature the steel’s permanent magnetism changes to induced magnetism and it will not be attracted by a magnet.
My point is you have to get the steel really hot before the structure changes and it can become brittle when quenched. I doubt that a couple of hundred rounds will generate enough heat to harden the barrel if it’s dunked in a stream. It will be hot enough to boil water and the stem makes a nice show, but it’s just being cooled, not quenched.
Here’s a M60 with a barrel that is probably hot enough to be damaged by quenching.
The bolt probably welded to the barrel. That’s what happened in Vietnam when guys kept linking belts, firing on very large numbers of enemy who were exposed and kept coming. Then they would do the same with the next one until it welded itself and the next…
As hot as that is, GE M134 Minigun barrels can get much hotter, past white hot to where they become translucent.
Back in the 60’s M134 barrels were good for 100,000 rounds. Now the Dillon Aero barrels don’t start erosion testing until 125,000 and most go to around 200,000 rounds. Metallurgy is always improving.
I don’t know what the life of GAU19 barrels is. It’s the M134’s big brother.
Electric guns are impressive, but I wonder if they can really take a strong EMP.
I've had many the 1919A4, (GPMG C1,4,5) glowing red hot like the M60 was. Matter of fact when carrying an M60 in Australia in 1977, we did live fire and I did that there too. The barrels always came back to serviceable. That was a point I always impressed on civilians when they talked about barrel life and how hot they got their hunting rifles and so forth...I'd explain "That ain't hot"...
I was on the UK trial of the Dillon minigun and our barrels were tested to virtually white hot, endless times. Intersting technical subject. I take the poiot now that tactically, our 'hot' ain't 'hot' in the metallurgical sense
Wouldn't it be nice if that type of barrel was open to the public like the Aero space ones they would be expensive but heck at 125,000 rounds before you check for throat erosion then that would last me 20 life times. At which point I would be older than Methuselah ever was.
Unless I am mistaken at the end of the clip there is a very noticeable drooping of the barrel.
Original (1970's vintage) M-134 "Minigun" barrels, (packaged by G.E., made by Harrington and Richardson, among others), were simply hard-chromed, full-length.
Interestingly, they are specified as having TAPERED rifling, probably to allow for thermal expansion, especially at the incredibly thin barrel wall at the muzzle. I have the drawing somewhere here in the crypt. The folk at H & R obviously had an interesting interpretation of "tapered" and also some idea of the acceptance gauging, as a bunch of these barrels I once inspected from "fresh in the wrap" appeared to have STEPPED lands instead of a "steady" taper. Probably functionally equivalent, just very odd to look at. MUCH easier to make than to have to grind a two and a bit foot long TAPERED reamer and expect it to survive long in mass-production mode.
HOWEVER, I do not recall ANY mention of a Stellite sleeve.
Despite dropping a few hints during an interesting day at Mr. Dillon's "toyshop" a few years ago, I have still not actually fired one. Can anyone verify the "rumour" that "Stellite" throated barrels (a la the M-60 barrel), were available (at additional cost)? This Dillon "glossy", http://www.idexuae.ae/exhibitorlibra...feb_2008_2.pdf does not go into too many barrel specifics.
Our early heavy GPMG barrels had stellite throated barrels that extended 8" or so into the barrel, that were specially made by Delora Stellite at Swindon. While the stellite part remained intact, the barrels just eroded as per usual AHEAD of the stellite liners and the extended barrel life was marginal. We had some of these barrels at Warminster. They were pretty expensive too at nearly 3x the cost of a standard barrel. It was decided that it was more economic to just have one standard type and replace those as and when required.
Well into the 80's I occasionally used to see old heavy stellite lined barrels painted yellow being used in the BFA role. Ideal for that because the throat just didn't wear out with blank. They were identifiable by the longitudinally machined lightening recesses in the rear of the barrels
Back to the minigun. We fired then out at sea while I was the REME/SASC engineering Offr on the trials. the impact of such a devastating amount of rounds hitting the sea looked just like the sea was boiling. Incredible............
PM
