M249 barrel melt by blanks?

[Dangerwing]

I am an OC/T in the US Army, and recently got into a "discussion" with another trainer. One of the soldiers going through our lane fired about 200 rounds of blank ammo through a M249 SAW cyclic - he never let up till the belt ran out. To avoid bias (and embarassment if Im wrong) I'm going to explain the argument in 3rd person, rather than identify which position was mine.

Trainer A felt that extended cyclic fire of blanks could damage a barrel just like extended cyclic fire of standard ball ammo. The reason being that the Blank Firing Adapter on the muzzle will keep the hot gasses inside the barrel causing heat to build and damage to occur.

Trainer B felt that extended cyclic fire of blanks will NOT damage a barrel because 1) the lack of bullets causing friction within the bore means drastically less heat will be produced and 2) blank ammo uses slow buring black powder that burns at a much lower temperature, thus again less heat will be created.

So, what do y'all think? Is trainer A right? Trainer B? Both? None of the above? Feel free to add your reasoning as well.

Thanks!

 

[medalguy]

I've fired a lot of blanks in my years in and out of the service. I've never seen barrel damage due to blanks, whether a BFA was used or not. I HAVE seen serious carbon buildup after firing blanks, and if you shot live rounds right after blanks, without cleaning the gun, you'd have a big problem. But I don't believe blanks alone would cause any problems. And 200 rounds of even live ammo wouldn't hurt anything. I've fired quite a few 250 round belts of 30-06 and 7.62 in one continuous burst and not damaged a barrel that I could tell.

 

[B.L.E.]

It's not bullet friction that erodes the throat of a barrel, it's the high temperature flames of the gunpowder.

I doubt that they use black powder in those blanks but black powder makes a lot of heat. I sometimes wear a leather glove on my left hand when shooting black powder skeet with my old open hammer double because the barrels get so hot. With smokeless powder, they only get a little warm.
The corrosive fouling of black powder would wreak havok on the gas piston of a gas operated automatic weapon.
However, blank powder most likely is a special composition engineered just for blanks. Pulling the bullet from a live round and shooting it in a rifle makes for a blooper load without the resistance of the bullet's inertia to generate pressure.

I'm inclined to believe trainer A because a blank has just as much or perhaps more powder in it as a live round does.

 

[chewie146]

Remember that pressure is really the function there and not the heat of the powder in and of itself. The pressure and duration of the intense heat on the barrel would be more important. The blank adapter would increase pressure, allowing the rifle to cycle, but to the same degree as loaded ammo? I don't know for sure. Friction would also be a factor, I would think. I've not messed with blank rounds much, but if you're seeing that kind of fouling from them, I can think of one of two problems with them. The first would be that the rounds are using a dirtier powder, as the manufacturer isn't worried about accuracy. The second would be that maybe the lack of back pressure from the lack of a bullet in front of the expanding gas would lead to less complete combustion. This is all, of course, theory, hypothesis, guess, and what I thunk. The blanks are most likely not black powder, as the fouling from that would end the firing before that belt ran out. Check out some of the G&A videos (I'll try to find a link) of them testing black powder shells in a modern, semi-auto shotgun.

 

[.45 Vet]

I don't believe the barrel would be damaged by the blanks. I am truely impressed that the DOD must have up-graded the training ammo. I never saw an old M16-A1 that would fire more than 1 or 2 twenty round mags of blanks before jamming. To think that the SAW would digest an entire belt is good news...

 

[briandg]

for many reasons, I don't even remotely think you could burn a barrel with that.

there are a lot of complications to my thinking, but essentially, I feel safe in saying that there isn't enough heat value contained in the powder in the blanks to do it.

Can it damage the gas system? can it foul it badly? erode it some?

Blank powder is more explosive and generates a high pressure high gas charge.

if it had been harmed, you wouldn't be here asking.

 

[R1145]

I've seen M16A1 barrels literally glowing red hot from firing blanks, so, yes, I think it is possible to damage a barrel using blanks.

 

[Mrgunsngear]

Is it possible? Sure, but it would take A LOT more than 200 rounds.

 

[blume357]

Would it not be easy to do a test and find out...

fire 30 rounds of ball ammo in one rifle and check temp of barrel
fire 30 rounds of blank in an identical rifle and check temp of barrel
repeat a couple of times

 

[Rob62]

I have fired LOTS of blanks through various full automatic guns during my time in the Army. And I can say without a doubt or reservation that they will not melt a barrel.

You can however get a barrel red/white hot by the continuous firing of blanks (or live ammo), and that this in and of itself does harm to the barrel metal.

Trust me when I say that you will by your own choice stop shooting long before the barrel gets anywhere near melting. The heat from a near white hot barrel is not something you will forget. And if you are any long term Machine Gunner, you will have some burns on your hands or arms from touching a hot barrel.

Side note - the longest continuous firing I did was about 500-1,000 rounds and the barrel while being VERY hot had not melted.

 

[raimius]

I've seen about 1,000-1,200 blanks go through an M240B in 10-ish minutes. It wasn't glowing yet, but it was smoking for about 20 minutes afterwords. So, yeah, you could definitely damage a barrel with enough blanks.

200 in 5.56, probably not (my guess)...
1,000+ yeah...

 

[blume357]

as a side note... my father was with a group of guys who melted the barrels on two browning water cooled machine guns one night in early Dec. 1950.

 

[Gunplummer]

I heard a whole lot of stories about melting barrels when I was in the military and could track down none. I would say the gun will jam long before that. I have seen the Belgian 240's when they started in tank turrets rip out loooong belts with out jamming. The German track guns are even more impressive. Sustained fire will eventually ruin a barrel, but melt one?

 

[Willie Lowman]

A few years ago at KCR, DeGroat ran his minigun till I could see the barrels glowing from behind the firing line. Forget about melting barrels, I wish I had the ammo it takes to just get the barrel that hot.

 

[langenc]

Ill go with A..

If I take my 257 WBY out and fire 8 or 10 as fast as I can it gets HOT.. Is it melting?? Id say yes at the leade..minutely.

When rifles are 'shot out' in couple thousand rounds--220 Swift had a reputation for that, I believe. What happened to the barrel to say it was 'shot out'?? Some (much??) of the leade and rifling will be gone.. How so--vaporized or melted?? Is there a difference?

 

[James K]

One point, the powder in those cartridges was blaNk powder, not blaCk powder. Blank powder, contrary to the story, is very rapid burning smokeless powder designed to generate high pressure and make noise without a bullet in front of it. That is why blank powder must never be used to load cartridges with bullets; the extremely high pressure will destroy the gun.

IMHO, it would not be impossible for the heat from excessive firing of blank cartridges to damage the barrel, but I can't prove that. I do know I saw the barrel of an M1 rifle turn near white hot and begin to droop after about 100 rounds of rapid fire.

Jim

 

[pvt.Long]

the barrel isnt damages with blanks as much as it is with live rounds.
" Trainer B felt that extended cyclic fire of blanks will NOT damage a barrel because 1) the lack of bullets causing friction within the bore means drastically less heat will be produced and 2) blank ammo uses slow buring black powder that burns at a much lower temperature, thus again less heat will be created." I doubt they use black powder is blanks. It is very corrosive and it doesnt burn slow it actualy explodes. Its deemed an explosive, that is why you cant go to bass pro and pick up a pound or two.

 

[B.L.E.]

Black powder is only classified as a low explosive due to its ease of ignition. It does not nor can it be made to detonate like high explosives. It burns so slowly that the "explosion" is nearly silent when a small amount burns unconfined.

 

[Willie Lowman]

James, my encyclopedia tells me that steel is white hot at 2190 degrees. White hot steel is pretty much liquid...

 

[B.L.E.]

The exact temperature of "white hot" depends on what your definition of
"white" is. Amber white, neutral white, blueish white. Ironically, photographers and artists refer to blueish white as a "cold white" and to amber white as a "warm white".