changing machine gun barrels in combat?

[navaho]

On "The History Channel", the show "The Tales of the
Gun" often talks about machine guns, and invariably
mentions how easy/hard it is to change the machine
gun barrel on that model.

I understand that barrels get shot out.

However what I don't understand is how often this
occurs, and even more importantly, does it really
matter?

It seems that most machine gun fire is used as
suppressing fire, so you can move up other troops.
As such, the gunner isn't doing precision aiming.
So going from 2MOA to 5MOA probably isn't noticable.

Of course, going from 5MOA to 10000 MOA (the bullet
starts going at right angles to where you're aiming
which means your own troops start taking hits) is
clearly a Bad Thing.

To summarize, I'm wondering:

Q#1: how often do people in firefights change machine gun barrels?

Q#2: how do they know when it's time to do the change?

Thanks!

 

[Mike Irwin]

I think gunners in the German army were trained to do it as often as they had the chance, often having two or even three barrels swapping back and forth.

The idea is to make your barrels last as long as possible.

A hot barrel wears a lot more rapidly than one that's been allowed to cool.

A barrel that starts to glow red hot (and they will, after not very many rounds) will rapdily become useless.

With a water-cooled gun, this isn't nearly as much of a probelm. As long as you have water for cooling, the guns can operate for MUCH longer periods of time.

 

[Rex Feral]

The barrels aren't normally "shot out" when they are changed. The object of barrel changing is to cool the barrel and prevent permanent damage.

When to change a barrel depends on the round being fired and the rate of fire of the weapon.

 

[Monkeyleg]

I was curious about that, too, after watching "Saving Private Ryan." There's the scene where the unit is going to approach the radar installation, and Tom Hanks' character talks about waiting until the machinegunner stops to change barrels. Makes sense. Too bad some of the semi-auto shooters at the range don't understand that concept when they shoot magazine after magazine until the foregrip melts.

Dick

 

[Marko Kloos]

That's why the German MG42/MG3 has a quick-change barrel. You pop a latch on the right side of the barrel housing with your palm, and the barrel slides right out. With a little practice, you can place the spare barrel container right underneath the quick-release latch so the barrel slides right into it. It's quite handy, and you can change the barrel in about five seconds. Just throw the new barrel into the barrel housing, slide it forward against the muzzle cone and slap the latch shut with your palm. If you kept Mr. Machine Gun loaded during the whole operation, you can resume firing immediately.

I never understood why the US Army copied most features from the MG42 and the FJG42, but left out one of the best features of the 42.

 

[Southla1]

"Saving Private Ryan." There's the scene where the unit is going to approach the radar installation, and Tom Hanks' character talks about waiting until the machinegunner stops to change barrels." They must have not changed it, after they took the site that MG barrel smoked for the longest. That part of the movie also shows why you either "take out" your enemy or make sure if you capture him he stays cpatured! Fast forward to the end and see who shoots Capt. Miller (Tom Hanks)!

 

[George Hill]

I dont know about PVT RYAN... But during Operation Just Cause I had to change barrels on my M-60. The barrel didn't want to cooperate and I had to grab it. I got the barrel changed and blisters to go with it. At the time however the burnt hand was a 2nd or 3rd level concern.

Dang I hate them 60s!
Mine worked fairly well.
Only jamed twice during various exchanges.

 

[kjm]

Changing on the 60 usually occurs after a belt of ammo (IIRC-100 rounds). About when you open a new can of ammo. One of the things I do know is that you just don't hold the trigger down until the barrel glows. You shoot 3-5 round bursts and allow your spotter to adjust your fire (assuming that you're using the T&E Mechanism.

We went to a school while we were in Saudi-Arabia and learned the fine art of machinegunnery.

George: The best way to avoid burns is to use those neat asbestos "fuzzy" yellow gloves that come with the MG. I suppose that you probably didn't have yours or that it was seen as unecessary weight.

Were you with the 82nd? Which unit? Heck, we might have met in the real world!

 

[K80Geoff]

M60

M 60 crews are supplied with an extra barrel and a large asbestos glove to change it out. I can recall in OCS a classmate of mine tried to change a barrel with his bare hands, spent the rest of the class cycle with bandages on his hand from the burns. This was after one belt (100 rounds)

I have seen barrels turn white from firing full continuous automatic. Air cooled barrels do have limitations.


Geoff Ross

 

[STLRN]

That is the benefit of the M240s and M249, barrel changes only take a few seconds. And imagine this the barrel handle actually helping with the change so you don't get burnt. Never could understand on the E1 versions of the M60 the bipod being part of the barrel group.

 

[George Hill]

No - I didn't have the mitten with me...
After 100 is a nice range rule but when fecal hits the fan things like that (and the glove) tend to get left behind.

 

[Jeff, CA]

You also want to avoid a runaway due to cook-off.

A acquaintance of mine told me about a time he was in charge of setting up a demo including an M2. He invited "an officer" to fire the gun, and the guy fired off a long, continuous string until the barrel got so hot the rounds were cooking off, so the gun was still firing even though the guy had let off the trigger. My guy frantically tried to break the belt while another guy poured canteens of water on the barrel.

 

[STLRN]

Jeff,
Your friend obviously knew very little about M2 operations. If it truly was a cook off situation, than it would have been more like single shots, not automatic fire. Per the MCWP 3-15.1 Machine Guns and Machine Gunnery. A runaway gun situation on a M2 may be caused by the following: (1) Bent trigger lever, forward end of the trigger lever sprung downward. (2) Burred beveled contacting surfaces of the trigger lever and sear. (3) Jammed or broken side plate trigger. The remedy for runaway gun is to replace the damaged or worn parts. The immediate action on a run away M2 is keep the gun laid on target and let the gun fire out all remaining ammunition. In an emergency, twist the ammunition belt. This causes the gun to jam, and normally will damage the feeding mechanism.(The belts on the M2 cannot be easily "broken").

[Edited by STLRN on 06-03-2001 at 05:34 PM]

 

[biganimal]

where and when did the 60 gunner get a spare barrel and mitton in the field????
I carried the 60 for 13 months and never saw a new barrel in the bush, we were issued a new barrel only if we were in camp. I fired several hundred rounds thru each barrel without any adverse effect during most firefights but I tried to maintain control and use 3-5 round bursts to maximise barrel life & to maximise squad life!!!! we didn't carry any thing into the boonies that was heavy except rats and ammo, not even socks!!!

 

[K80Geoff]

Spare barrel and mitten

Big animal... why of course you had spares. The TM says so!

In Vietnam the M60 was often used as a squad automatic weapon, or so I have been told by people who were there and should know. Like everything else, spare barrels and mittens would be extra weight and would probably be left behind. No tripods and T & E either.

I do remember in my non combat experience at Ft Benning we never carried any spares, in fact M60's were never assigned a loader or ammo bearers like the TM says. Everyone in the squad carried a box of belted 7.62 for the M60. In our case they were blanks of course, but from the instructors I got the impression that this was SOP "over there".

I doubt that in the middle of an ambush you are going to worry about the barrel burning out.

In a different time and place things may be different. I bet Mech troops carry all the goodies, since they don't have to hump them all over the map.

An old Platoon Sarge of mine who was a young soldier in the Korean War told me how they shot the barrels on Quad 50's white hot during chinese human wave assaults. When the nastiness was over the barrels actually drooped from the heat. They let them cool and shot them again if the chinese came back before they could be changed.

I suppose we could add this to the list of military axioms.

"When the fighting starts throw the TM away."


Geoff Ross

 

[Jeff, CA]

STLRN, everything I said is exactly per your quoted instructions. The gun continued to fire, repeatedly (how fast he didn't say). In saying "break", I meant "disconnect", as in, pulling a round out somewhere away from the gun so it will shortly run dry. If you'd like to take the matter up with my friend, let me know and I'll give you his phone number.

 

[STLRN]

Sure I am more than willing. Your friends assertion that because an officer fired the too long a burst is what I was referring. Was it a cook off or a run away gun? If it was a run away gun, than the weapon had broken or worn part, not an overheated barrel.
A run away is when a gun continues automatic fire after you have released the trigger (butter flies). A cook off occurs when the intense heat of the barrel, causes the unintended firing of A cartridge. A cook off with a 50 cal would be single shots, and only after each round had sat in the chamber for at least 10 seconds per round. And the best cure is rotate the bolt latch release to the unlocked position, making it an open bolt weapon. Not attempting to strip rounds out of the belt.

 

[Gonzo_308]

My AG had a spare BBL with him and kept it strapped on the back of his ruck in it's case similar to a billiards cue case. I was taught to repeat the phrase "fire a burst of six" every time I pulled the trigger and when the sentence was done re-aquire a target and repeat my mantra. It worked well for me. we would also linkour belts so that we had 200 rds going we would change bbls whenever it was convenient. reloads always seemed like a good time since the system was out of action anyway.

 

[Bruegger]

Runaway gun

Like STRLN says, this comes from wear on the gun. One way you can get this is if you fire too many bursts that are too short (wears out the sear).

When to change a barrel depends on the weapon and the rate of fire. You can basically fire all day at the "sustained rate," but if you're mowing down human wave attacks and firing at the cyclic rate, you'll be melting those barrels into limp noodles if you don't swap them out (repelling human wave attacks is an exception to the rule, though). Even firing at the rapid rate, which is more like what you'd do in combat, you'll need to swap those barrels frequently.

Not swapping out hot barrels causes rapid wear on the barrels and can warp them. NCOs need to make sure all the guns and barrels get rotated into use, so you don't have one or two totally thrashed guns.

If the Army really doesn't issue spare barrels for their MGs, even for squad automatics (and I really doubt this is true today), they're playing with the lives of their machinegunners. Not carrying spare barrels to save weight is "penny wise and pound foolish." Why not leave the ammo home, too, to save weight?

One word of caution: don't put the hot barrel into the spare barrel bag, and if you do, don't sling that thing over your shoulder. Ouch!

Semper fi,
Bruegger out.

 

[Marko Kloos]

Our spare barrels came in nice, round metal containers with snap locks and carry slings. You could drop a hot barrel in them, close them and be on your merry way without burning your back.