We’ve all heard about 6000 rounds per minute, but I doubt like hell that one of those things could continue to fire for a full minute.
Assuming an unlimited supply of ammunition, how long could they keep shooting?
It’s actually two questions, How long could it go BRRRRRR before something bad happened?
More importantly, it could fire a one second burst every…five seconds? minute? what?
I don’t have a factual answer. The one time I saw one in action in 'Nam, my recollection is that it was firing 3-5 second bursts, but that was over 40 years ago, so my memory may be faulty.
The article in Wiki says:
which works out to just over 50 rounds per second.
The ammunition box would be empty long before any risk of damage or overheating. It can safely be fired in a single 4000 round burst if you wanted.
It’s 3000-4000 rpm, not 6.
Sure can.
The average rounds before jam is something like 30,000 rounds but that isn’t a permanent stoppage. The barrels are good for about a quarter million rounds fired. So its somewhere between that.
You will deplete your ammo box in one minute. That’s pretty bad.
Here’s one firing for 45 seconds (though the clip doesn’t show the full 45 seconds).
Here’s the presidential motorcade one showing off a bit.
I work across the street from a major airport and have seen that one (or one like it) quite a few times. We always joke to people ‘you should go drive up behind the motorcade’ to people, then point out the last few cars with the windows down/flipped up have guys with big guns in them and then point out the Suburban with the minigun and show them that clip.
Yeah, you probably don’t want to go racing up behind the motorcade.
To be mildly political, I’m a Republican and am no fan of Obama in any way. But I would still absolutely love to see his Secret Service detail defend him with one of those*!* 
And for what it’s worth, I believe that even most WWII fighters with regular machine guns could exhaust their ammo if they held the trigger for no more than about 15 seconds…
Kari, in a dress and boots, firing a minigun(Clue!).
I’ll be in my (ammo) bunk(er).
FWIW, I’ve been working in this spot since the early 90’s and I’ve seen 4 presidents regularly drive past with pretty impressive motorcades. I don’t recall when I was first made aware of the minigun, but I’m fairly sure the guys hanging out near the end with ‘regular’ guns have always been there.
What I always thought was funny was one time when GWB was in town. You always (well, I always) heard about how in the confusion of the motorcade*, you can usually spot multiple identical limos so you that you won’t know which one the president is in…there’s GWB, waving out the side window. Only time I’ve ever actually seen one of the presidents.
*There’s usually a lot going on. Early in the morning there’s barricades dropped off at all the intersections on the route. About two hours before you start noticing a lot of cops buzzing around. An hour or so before, all the cops stop driving an position themselves at every single intersection and driveway that enters into the main road in front of store (and I assume the entire route from the airport to the destination). We’ll see a Coast Guard helicopter flying around overhead. From what I’ve been told, they’re checking out roof tops. Air Force One touches down and taxis to the Air Force base. About 15 minutes later the police close the road. If it wasn’t for the side street all of our customers would be stuck for the next half hour or so. Eventually you hear and then see all the motorcycles, the 10 or 15 piece motorcade, a handful of cops, usually an ambulance, news crews and then, depending on the president (Obama hasn’t done it) the end will be filled with off duty (but paid IIRC) bike cops that are really just there for the ride along. It passes, the cops that have been sitting there on the side of the road open everything back up and it returns to normal. A few hours later the whole thing happens in reverse.
The rate of fire used was indeed 6,000 rpm on the initial application of such guns in SUU-11 aerial gun pods, three of which were fitted to AC-47 gunships. Eventually the rate was reduced in that application*, and it’s also lower in the flexible mount applications as usually seen on TV/video’s.
In the original SUU-11 set up there were 1,500 rounds per pod which could be fired off continuously, in around 15 seconds, before a fairly lengthy pause for manual reloading. So that’s 250 rounds per barrel, which is nothing remarkable for continuous fire from an air cooled machine gun, especially with the cooling air flow of even prop airplane speed.
The pods could be reloaded multiple times in a sortie. The same reference as below quotes the record through October 1966 as 43,500 rounds by a single AC-47 in a single night, or 2,700+ rounds per barrel.
There may be imprecision in the question or some responses about ‘sustained’ fire. AFAIK in correct machine gun terminology that’s the number of rounds that can be fired in a single continuous burst, which would be limited by barrel heating. It’s not the barrel life, which is the total number of rounds before the rifling is worn down, but which assumes pauses in fire to allow the barrel(s) to stay below their maximum operating temperature. The barrel life is 1,000’s of rounds for any decently made machine gun barrel. But an M134 type minigun like any other air cooled machine gun would overheat in a continuous burst of several 100 rounds per barrel. Although with 6 barrels that’s a lot of rounds, more than are held ready in most applications/mountings, and it typically takes awhile to reload. That’s in contrast to say a regular single barrel air cooled machine gun which you can easily overheat by pausing fire only long enough to quickly load new 100 round belts.
You generally need water cooling for literally sustained (no pause or just few seconds to load a new belt) fire of 1,000’s of rounds per barrel, from a barrel heating standpoint (and without changing barrels, which is an option on single barrel guns), also assuming nothing in the mechanism breaks.
*in the fall of 1967, after around 3 yrs of combat operation in Vietnam, to reduce consumption of mechanism spares and increase barrel life, per the official history “USAF in Southeast Asia-Development and Employment of Fixed Wing Gunships 1962-1972” p. 57.
I have to admit I didn’t expect that! Though it might be a bit tricky to use it in an urban area.
The spent rounds piling up around her feet reminds me of the scene on the boat in Hot Shots Part Deux 
Actually, if you let it play, you’ll see the gun firing for over a minute. I’m disappointed they didn’t use the gun from a Warthog.
“Sustained Rate of Fire” is the number of rounds per minute that the weapon system can theoretically fire indefinitely without sustaining damage.
When the machinegun’s cyclic rate of fire is the same as its sustained rate of fire, the answer to “how long could it fire if it had an infinite belt of ammo” is “however long the barrels hold up!”.
It isn’t like any other air-cooled machine gun. First of all, the barrels are spinning. That convection increases the cooling effect of the air. It cannot be compared to other single-barrel machine guns.
Second, the load is shared among 6 barrels and each barrel gets a slight rest and cooling loop between each round. So when the weapon is firing continuously at 3,000 per minute, each individual barrel is only firing 500 rounds per minute. That is a slower rate of fire than pretty much every single barrel machine gun out there. It can keep up that pace for several minutes at least, which–in practice–is two or three times longer than the 3,000 round ammunition box will last! It’s going to be a long time before those things turn red, and a little longer before it breaks. The average rounds fired between jams is 30,000. I’m sure it can get to 30,000 on cyclic without destroying itself. Remember, this OP did not state that the weapon is ever going to be used again, or what’s safe for it. The OP wants to know how many rounds will it fire before “something bad happens”. That answer is so high, there really isn’t an accurate response. It would require an experiment where we intentionally destroy several miniguns and take the average of rounds fired before total malfunction. Who’s going to do that?
This is why barrels are changed out. Every machine gunner carries an extra barrel which he changes out ever minute or so depending on his rate of fire.
Thousands, sure. But the M134 can be set for 3000 or 4000 rpm. It’s not firing 6000 rpm. Maybe older models did at one time, but I’ve never worked with them.
The British WWI/WWII Vickers Machine Gun - which was water-cooled - was once fired continuously for a week, having the barrel changed every hour, and put five million rounds downrange without stopping or jamming.
There are numerous accounts of the design giving prolonged periods of sustained fire (many hours) in combat as well.
I don’t agree there’s such a standard definition, and I think it’s a source of confusion in the question and thread.
The ‘theoretical sustained rate of fire’ would simply be the cyclic rate, assuming ‘theoretically’ that there’s no barrel heating limit, as well as no stoppages or mechanical failures, and no reloading time (just continuous belt(s)). But in practice there will be a barrel heating limit, and it’s likely to be the binding constraint on a mechanically reliable air cooled machine gun with unlimited ammo feed. A reasonable inference would be that this on the same order for a minigun per barrel, as a conventional air cooled machine gun, and no reference or cite has been given to the contrary.
It’s true the minigun has air flow over the barrels sitting on the ground at sea level. OTOH air cooled machine guns in aircraft traveling at 100’s of mph in cold air at high altitude still were constrained by barrel heating. For example, the M2 .50 cal a/c machine gun had a stated limit of only 75 rounds in a single continuous burst followed by one minute of cooling, because of barrel heating (see standard ordnance sheet reproduced in “The American Arsenal” by Hogg, p. 223). In practice fighters and bombers fired much longer bursts with these guns, fighters typically had ammo loads of at least 250 rounds per gun, but it was also common to burn out and ruin the barrels on a single mission, as noted in innumerable accounts of the use of these guns in a/c. This gun had a relatively light barrel, the mass of the barrel as a heat sink is a key factor in its heating limit (~10lbs, not to be confused with the related M2 Heavy Barrel machine gun which is still used in ground applications and has a ~27 lb barrel). But it illustrates the constraint. There’s no reason I can see to believe a minigun’s barrels are immune to it.
Which is why I was careful to note in every reference in my post rounds per barrel. As for example the AC-47’s SUU-11 pods, 1,500 ready rounds per pod, 250 rounds per barrel before a significant pause was needed for reloading, where the barrels would also have a chance to cool. That’s not so many rounds to fire continuously per barrel; the minigun might have more resistance to heat than the M2 air cooled (…just no reason to think and no reference given to show it’s many times as much). However that was only ~15 seconds of continuous fire at the cyclic rate then used.
Cite besides appeal to personal authority?
Again this is not typically the constraint for continuous fire from otherwise reliable air cooled machine guns.
But that just reinforces the point that barrel heating is the typically binding constraint on otherwise reliable air cooled machine guns sustained fire, and the minigun is basically an air cooled machine gun.
The flexible ground/helicopter mounts in recent decades fire at the lower rate. The gun pods used on gunships (firing sideways) and as underwing stores on attack a/c back in the 1960’s in fact fired at 6,000 rpm and successfully so (the cut back in 1967 was in part because of a particular shortage in spares for the new MXU-470 type module then introduced on the gunships in lieu of just mounting the SUU-11 pods). I just wanted to clarify that.
I’m just curious about what you mean by this. It’s my understanding that since the gun is electrically driven rather than gas-operated and doesn’t rely on the firing of one round to chamber the next that any misfires are simply dragged out of the chamber and ejected. This being one of the major selling points for the use of either electrically driven rotary guns or chain guns on aircraft where one can’t simply step out on the wing to clear a jammed round.
Maybe something goes wrong in the delinking system?
That is the definition. You don’t get to make up your own meanings and say they are the cause of confusion. Sustained Rate of Fire is understood to be the rate at which a weapon can continue to fire without being damaged. You stated, “AFAIK in correct machine gun terminology that’s the number of rounds that can be fired in a single continuous burst, which would be limited by barrel heating.” And that is simple not the case. For example, the Sustained Rate of Fire for an M16 is 12-15 rounds per minute. Those rounds are not fired in “a single continuous burst”. A person can safely fire 12-15 rounds per minute from an M16 indefinitely without having it overheat or otherwise fail from use. At the sustained rate of fire, your limit becomes the regular expected barell life, which for the M16 is about 8,000-10,000 rounds.
You also need to understand that the weapon will not immediately explode if you shot it at it’s cyclic rate (800 rounds per minute). It can easily fire at this rate and empty an entire 100 round drum without sustaining damage. And, if the shooter wanted to, he could keep feeding it magazines and firing on cyclic. Emptying each magazine in a couple seconds of trigger pull and putting in another. This is not the Sustained Rate of Fire, because eventually this weapon is going to overheat and malfunction. However, it can actually keep this up for quite a while.
More importantly, it’s going to show evidence of overheating long before it actually stops functioning. It’s going to turn red or grey, it’s going to smoke, it might catch on fire. All the while, it will keep shooting. You’ve only reached the half-way point.
See this torture test of an M4 https://www.youtube.com/watch?v=Kzfm4pYhIyY
The minigun in the Mythbuster’s video shows no evidence of heating up. It’s not even starting to get red. The minigun can handle the entire box of ammo (3,000-4,000) rounds with no problem. It is designed to handle long bursts like that. Eventually, if someone had a 50,000 belt of ammo, it’s going to overheat and malfunction. But that’s not going to happen at 6,000 rounds! See the 2min mark of this video to see a minigun that’s starting to get warm and starting to glow. That didn’t happen from one ammunition box! https://www.youtube.com/watch?v=EvYekK5k844
There is no such thing as “theoretical sustained rate of fire”. You’re making up terms again. You cannot “assume” there is no barrel heating. Barrel heating is the whole point of having a sustained rate of fire. My point about the minigun was that it’s sustained rate of fire is damn near it’s cyclic rate. That’s a bit of an exaggeration, but the minigun could easily fire, in one continuous belt, all of the ammunition you could have possibly brought along. The OP wanted to know, though, if a person had infinite ammo, when would it break. You’re not going to find that in any cite. I can say confidently that it will be somewhere between 12,000 and 30,000 rounds. That doesn’t mean it’s going to work again. But, like the M4 in that video, it’s going to fire until its last breath.
No shit. So would you care to take a reasonable guess at the OP’s question? You seemed to be saying earlier that it couldn’t possibly fire an entire ammunition box of 4,000 rounds without melting even though there is a video linked in this thread of it doing exactly that! They fired it for over a minute continuously. That was over 3,000 rounds right there and it wasn’t even RED yet! Guns show evidence of overheating long before they fail from the heat. See another example here:
A reasonable inference would be that it would turn red long before it ever failed. It wasn’t red after a single burst of over 3,000 rounds. It is reasonable to assume that it could keep going for at least another 2 minutes, yet somehow you’re convinced it would fail before 3 minutes. What kind of reference or cite would you like? Do you think there is published documentation of how many rounds it will fire continuously before it melts? If you can find that, please let me know. In the meantime, I will apply common sense and deductive reasoning. Barrels get red when they are hot. Barrels can keep on going at least 200% longer than the time it took for them to turn red. If a gun fires 3-4,000 rounds without turning red, it can fire at least 12,000 before coming apart and probably another few thousand as its coming apart.
What do you think happens if they fire 80 rounds in a burst? Do you think the whole thing blows up? The OP wants to know how long before something “bad” happens. Something “bad” is not going to happen to the M2 from firing an 80 round burst. I’m starting to think you’ve read a lot of books, but haven’t done much shooting.
They’re not immune. They just aren’t going to melt after only 4,000 rounds.
Thicker barrels firing a smaller cartridge at a slower rate. And spinning. You can’t think of any reason at all? There’s four right there, and I’m sure there’s more. Barrel lining perhaps.
Who cares!? It’s relevant to the question in the OP. Did you forget there is an actual question being asked?
Firing at a much slower rate per barrel than typical 7.62 machineguns. Slower rate equals longer bursts, and more rounds before melting.
The Dillons jam far less than the GE ones but, they can still have problems at the feeder/delinker, during extraction, or with the electrical system. 30,000 rounds between jams is insanely reliable, though. That’s one jam for every 10 ammunition boxes.
Thanks for the explanation.
It must be the kid in me, but I was pretty amused that he kept firing single shots after the gas tube failed and the handguard was on fire(!).
FWIW, a 20 mm M61A1 has a high rate of 6000 rounds per minute and a low rate of 4000. Typically an F-18 has almost 600 rounds carried so you can run through that pretty quickly. Of course, throwing 50 20mm /sec at something is going to reduce it to scrap in short order…
It’s pretty cool to see what that does to a sea container BTW…
