M-60 question

My Guard unit still had Sixties when I first got there. Similar warnings abounded about working the gun too hard, though we were more worried about a runaway gun than total structural failure. I had fun with it until we got the M-240B.

I carried a M60 for most of my time in the Army. I got the barrel hot enough to bend slightly (warp), I've had cook-offs, but never got one hot enough to fall apart from heat expansion. Not saying that it couldn't happen, just that it never happened to me.

I have a lot of experience with the 60...got the barrel glowing a few times but never had anything fall off.

I have also never seen "accurate and sustained fire" with one. The 60 is a suppression tool...you don't fire at individuals, you fire at an area, or rather, in front of an area. The expectation is that both primary projectiles (the bullets) and secondary projectiles (rocks kicked up) will pin the enemy down or take them out.

You don't snipe with a 60.

Sometimes those decorations utilize a bit of creative writing in them...this does not take away from what he accomplished, it only reflects that the document was nto written by a gunner.

I'm wondering how you get a 'cook-off' with any MG that fires from an open bolt, like the M-60??

The only way a round could cook off is if it was a mis-fired dud round, and stayed in the chamber long enough to get hot enough to cook off.

rc

rc, how then does a "Runaway gun" occur? Every time I go to qualify or shoot a M249 or M240, we are warned about what to do if we have a "runaway gun." Would that be if the sear somehow fails to stop the bolt? It's even simulated in the EST-2000 simulator if you fire continuously @ a target, I think.

a few rounds cook off at the end of this video
http://www.youtube.com/watch?v=X8rHKGkaOQk&feature=player_detailpage

backbencher said:

rc, how then does a "Runaway gun" occur? Every time I go to qualify or shoot a M249 or M240, we are warned about what to do if we have a "runaway gun." Would that be if the sear somehow fails to stop the bolt? It's even simulated in the EST-2000 simulator if you fire continuously @ a target, I think.

Click to expand...

Normally it is from an excessively worn or broken sear. It can also happen in semi-auto firearms if the sear is too worn to engage the hammer and it essentially slam-fires until empty. Quite a significant emotional event, I am told.

The problem (well, one of them) with the M60 is that if you only pull the trigger just far enough to fire, the bolt will bump into the sear as it goes back and forth. Over time, this wears down the sear, eventually getting to the point that the bolt will just jump over the sear even when the trigger is fully released. That results in a runaway gun.

I've never experienced it, but my understanding is that the correct action in case of a runaway is to twist the belt so that it jams in the feedway.

As for guns coming apart when heated up, I haven't heard that from the folks I've talked to. The construction was relatively light to save weight, though, and I wouldn't be surprised if heavily used guns would start to have pin holes egg out or rivets and welds crack or loosen. That could easily be mistaken as being caused by overheating by someone putting a lot of ammo through one of them.

We were told NOT to twist belts if we didn't want our digits massaged by the tender bolt & feed mechanism.

What's the alternative to twisting the belt?

Hang on and let it run till it runs out of ammo.

Twisting a cloth belt, or twisting and breaking a disintegrating link belt to stop a runaway gun is almost as old as MG's.

I imagine Hiram Maxim and John Browning did it a lot more then once in the development stages of early MG's.

And I still stand by my orginial questioning statement.
An open bolt MG cannot experince a 'cook-off' because there is never a live round in the chamber until the bolt chambers and fires it.
(unless the round is a dud and did not fire when it was chambered for whatever reason)

A closed-bolt auto like an M-16 can have a cook-of in a hot barrel.
Because a live round is chambered every time it fires, and can remain unfired in the chamber until it gets hot enough to cook off.

An open-bolt design cannot.
Thats why all successful MG's of the last century feed & fire from an open bolt.

As for the Youtube vid?
Just because somebody can afford a 5 or 6 figure M60 and enough ammo to melt it, doesn't necessarly mean they know what a cook-off is either.

rc

rc, how then does a "Runaway gun" occur? Every time I go to qualify or shoot a M249 or M240, we are warned about what to do if we have a "runaway gun." Would that be if the sear somehow fails to stop the bolt? It's even simulated in the EST-2000 simulator if you fire continuously @ a target, I think.

Click to expand...

it can happen from any semi or full auto. ive heard stories of it happening to the 40mm bofors caused by a worn part. they simply let it run out of ammo.

ive also heard allot of stories of "it can happen" to the 25mm gau-12. but i dont recall ever talking to anyone that ever had it happen

The only possible way "it can happen" to the 25mm gau-12, or any other of the Gatling Gun aircraft cannons, would be a stuck electrical solenoid or wiring short.

They are spun up to speed by an electric motor, and nothing else can possible make the gun run away, or even fire once, unless the electric motor is spinning them out of control and there is no way to shut off the electricity to it.

Even then I'm pretty sure there are other controls / shut-off's / fail-safes on the arming switches, feed troughs, and ammo cans that would have to be shorted out of commision too before the gun could run away.

rc

An open bolt MG cannot experince a 'cook-off' because there is never a live round in the chamber until the bolt chambers and fires it.
(unless the round is a dud and did not fire when it was chambered for whatever reason)

A closed-bolt auto like an M-16 can have a cook-of in a hot barrel.
Because a live round is chambered every time it fires, and can remain unfired in the chamber until it gets hot enough to cook off.

An open-bolt design cannot.
Thats why all successful MG's of the last century feed & fire from an open bolt.

Click to expand...

Not true. The M2 BMG fires from a closed bolt, and given that it's currently the oldest small arm in our arsenal, and in use with all our NATO allies, and lots of other countries besides, I'd certainly say it would have to be called a "successful" MG.

And for that matter, all the various Maxim variants -- certainly successful MGs as well -- fired from the closed bolt, as did the water cooled Browning M1917. When the gun was redesigned as an air cooled weapon, and designated the M1919, it was changed to fire from the open bolt. The water cooled version, which remained in use during WWII, always fired from the closed bolt, however.

O.K>!
You got me there.

But an M-60 doesn't fire from a closed bolt, and even if it has it's short-comings, cook-off's isn't one of them.

rc

M60 was the biggest piece of crap ever made. Constantly jammed and would knock the fillings our of your teeth (helicopter use hung from a bungie cord)

M60 was the biggest piece of crap ever made. Constantly jammed and would knock the fillings our of your teeth (helicopter use, hung from a bungie cord)

Apparently experiences differ.
I used the M-60 off & on from 1964-70.
I liked the M-60, A lot!

Perhaps if you had used or humped a Browning .30 MG & tripod before the M-60 came along, your view of them would be different too?

They were never designed to be hung or fired from a bungee cord in the first place.

That was a result of a lack of proper helo mounts, and field expedient methods to improvise and overcome during Viet Nam.

The new Huey doors & the new M-60 crossed paths faster then the two could be adopted to each other.

I'll just say you were much better off with a M-60 hanging on a bungee cord then a Browning .30 hanging on a Bungee cord!

And leave it at that.

rc

My wife's uncle has a colt gold cup that will do mag dumps because it is so worn out.

I used an M-60 in Viet Nam as a door gunner, I think it was one great gun. That is until the mini gun.

The M-60s we used in 1970 held up well for us. Someone would burn out a barrel fairly regularly so each AG carried a spare for their gun. I know we once had a cracked bolt lug but it wasn't discovered until the gun was broken down for cleaning after action so there was little drama associated with that discovery. We started carrying spare bolts after that though.
We were 1st Cav so the door gunners for the slicks were recruited from our gunners when they were getting short so we kept in touch when we'd see them and I don't recall any complaints from those guys. They used their guns more often than us but had better access to the maintenance shops. The slicks all had pintle mounts. I think some of the Loches (LOH: scout or "light observation helicopters") hung guns from webbing straps. I can't imagine trying to accurately shoot an M-60 hung from a bungy.

My Dad (25th Infantry RVN 68-69) said he never saw an M-60 (He called it "The Pig" during our conversation) self-disassemble like that, but he has seen barrels get hot enough to light cigarettes and cigars on contact.

Just my .02,
LeonCarr