how hot?

[sharmanajusmc]

for those of you with full autos how hot would you think the actual reciever gets during sustained fire? more than 500 degrees where it meets with the barrel jacket?

[JBaum]

If the barrel jacket gets that hot, you're already late for changing the barrel. The barrel is to be changed after 250 rounds tops.

[amafrank]

The receiver won't ever get anywhere near that hot. . . though the muzzle end may get a little toasty. When the barrel is glowing red you can still grab the barrel extension bare handed and pick the barrel up by it. Radiation heating of the shroud may get a few degrees into it but while it may be too hot to touch with your hands it won't normally boil water in my experience.

Frank

[42rocker]

Somehow I remember a cooking with DA and Bil show using a mg42, or was that someone else. Bacon wrapped barrels and some other things being cooked..... Enjoy Life

Remember if your barrel burns the meat you need to change barrels. As jbaum states 250 rounds more or less. I think that it was 150 Full Auto, no real breaks.

Later 42rocker

[Mike]

We have got the front end hot enough to light WD40 we sprayed on it to cool it down.
Have turned a couple barrels bright red and the nozzle a dull red a couple time.

The barrels we turned red did not have any rifling left, tracers were going all over the place cork screwing.

[DARIVS ARCHITECTVS]

The barrel will get over 300 deg F if you run 500 rounds through it quickly. It's a bad idea, since the rifling starts wearing very quickly at that temperature. Shooters should show a little know-how and change the barrel before it gets that hot.

[junglewalk]

DA is right, change the barrel.....the german army of WWII stressed short controlled bursts with the 34 in the field, and also in training Fortress troops in the 1930s for posting in the West Wall, being most all MG mounts in the pillboxes and bunkers were designed for mounting the MG-34. Each MG had only a few barrels, and in a prolonged defence, burning out one barrel after the other was not the answer in keeping enemy infantry carrying demo charges away from your nearby pillbox, or your own.....
.......unless you guys were just burning out barrels on purpose?
.......
.......Sustained machinegun fire has always been a problem for most mg gunners of all armies.......In 1968-69 the M-73 mg that was coax-ually mounted next to our 90mm main gun on our M-48A3 tanks in Viet Nam, did have a quick way of changing barrels. It was similar to the MG-34, in that the receiver pivited away from the barrel jack, so the barrel could be pulled out with a asbestos glove.....but, we did burn up some barrels in fire-fights with the NVA, and even cal.50 barrels of the M-2 would be glowing red! That barrel was impossible to change quickley, and not done under fire.
.....Give those barrels a break, we are getting down to the bottom of the barrel, when it comes to the limited supply out there.........bh

[sharmanajusmc]

how long after firing 250 rounds and changing the barrels would it take for it to cool enough for firing again?

[amafrank]

if you drop it into a bin full of water it will cool in about 20 seconds. Aircooling or dropping the barrel in the sand will affect the cooling rate in a variable manner. The steel for these barrels was very good quality though the rest of the gun is mostly mild steel. . .

Frank

[drooling idiot]

if you drop it into a bin full of water it will cool in about 20 seconds. Aircooling or dropping the barrel in the sand will affect the cooling rate in a variable manner. The steel for these barrels was very good quality though the rest of the gun is mostly mild steel. . . Frank

I'm sure i remember reading in one of the German army field manuals not to lay the hot barrel down on the bare ground. I interpreted it as a caution the barrel could warp if it was cooled unevenly. do you think its a good practice to flash cool a really hot barrel in water?
I think I'd prefer to do that only if i found myself staring at a hoard coming my way and didn't have a better option.

[junglewalk]

DI you are right;..> dropping the hot barrel into water may cause it to bend as you say......Lay the hot barrel in the open barrel carrier, and I used to spray oil onto it, & let it cool....Now I spray a non-chemical spray ,'Olive oil Pam' now. No flash flame rising up and I spray away, & cools fast......bh

[Bil]

Also,if you spray with Pam,the bacon doesn't stick! Right,DA??? Now to figure out how to cook the eggs.... ---bil

[junglewalk]

Can't have the bacon stick~!
.....Some of us WWII re-enactors used Olive Oil Pam to break in new leather, like the new-made slings for the 34/42, etc.....
......On the Jungle Walk course during the MG shoot at KCR, with run after run, we use Pam on the Uzi, to lube action & cool the barrel. (makes the shooter think he is in a Olive patch)
..We're hooked!....bobh

[Matt]

anybody know the temperature of a hot mg34 mg42 barrel after a full can of ammo? i realize there are several factors involved but just curious if anyone has measured it? - matt

[DARIVS ARCHITECTVS]

Also,if you spray with Pam,the bacon doesn't stick! Right,DA??? Now to figure out how to cook the eggs.... ---bil

The guy who fried bacon on the MG-42 barrel? That wasn't me, Bil. I take better care of my stuff. It does show that those barrels get awfully hot though!

[Matt]

what temperature does bacon fry at?

[Bil]

Check DAs lomg post over at the Bacon Lovers Forum. Lots of good info and pics,including Canadian bacon! ---bil

[Matt]

I just ate lunch and I am feeling hungry again!

[TactAdv]

for those of you with full autos how hot would you think the actual reciever gets during sustained fire? more than 500 degrees where it meets with the barrel jacket?

For like, $13.00, Harbor Freight has a cheapy laser temperature monitor made by the Celestials, that looks like a little radar gun, that seems to work well. They actually offer two models, one goes to 700F, one to 1600F.

I haven't zapped my MG-42/MG-74's yet, but I have used it with other things like suppressor bodies when we were doing development, it seems to be good, accurate, to about 2-3% of more precise methods of measurement and probably worth the couple bux to have one handy if you care.

-TomH

[TactAdv]

DI you are right;..> dropping the hot barrel into water may cause it to bend as you say......bh

It's not so much that, "bending", as it will cause the micro-crystalline grain structure to become embrittled. In typical high grade, high-carbon steel as was used in these barrels by the Germans, the problem becomes one of altering the initial quench, which then can lead to altering the austentitic-martensitic crystalline balance and hence, uniform grain structure. It's called, in metallurgists parlance, "un-cementing the grain".

If cooled rapidly in water, repeatedly, a weak form of hydrogen embrittlement may set in, as well, depending upon the individual succeptability of the alloy.

Typical bored and rifled barrel construction methods of the day do not lend themselves well to rapid water-cooling, modern barrel making techniques and modern ordnance steels are much more tolerant of the practice. In particular, hammer-forged barrel making seems to tolerate the tendency for grain structures to change much better.
-TomH