why no cooling fins on LMG Barrels?

[c_canuk]

I was wondering a while back why the LMGs and GPMGs barrels don't have fins on them to increase their surface area and speed dissipation of heat to the air... I imagine they would be in the way if they were too large but surely even smaller ones would allow for a few more rounds down range.

what about as an attachment could be added for defensive operations, perhaps with an port to put an inverted canteen on to add a slow drip down the fins using the port for the C4 Mask... *shrug*

just wondering if this topic has been explored and abandoned for some reason

 

[KevinB]

Fluting is a much better option for cooling than fins - fins are fragile.

Some barrels - like the MK46 (SOF version of the C9 Para) are fluted.

  For water cooling it requires a LARGE amount of water - look back to the WWI VIckers and Maxim....  makign the gun impossible to move quickly.

 

[Colin Parkinson]

Would it be useful to supply a limited number of watercooled barrels for base defence and with the newer coolants you could reduce the quantity of water? The Vickers was heavy but could fire all day, certainly a nice feature when dealing with hordes. But you are right that carting one would be a bit*h. 

 

[KevinB]

M134 minigun - the answer to high rate of fire -- its easier to have mulitple aircooled barrels than one water cooled.


these days due to tolerance - improvements in steel and design - it is easy enough to get the weapons to work well enough at a reasonable rate of sustainable fire that you dont need liquid cooled setups.

 

[Colin Parkinson]

Doesn't the mini gun then tie you to a power source? not to mention a good supply of ammo! Can you adjust the rate of fire?

 

[Carbon-14]

do the barrels heat up a lot more while using blanks than ball then? cause the amount of time that it took a the gas selector to get nice and hot enough to make a combat glove smoke, wasn't very long even though we were using short bursts.

I had heard of the Vickers, and from what I understand, cooling was a heat pump operation where water would absorb heat and then dissipate it from a radiator, using a phase change (water - steam) technique, where you don't care about retaining the water, would allow you to dissipate a lot more energy, you just gotta keep adding water...

A mini gun is a better system, but not as easy to carry around compared to an LMG or GPMG right?

*shrug* if ball ammo doesn't heat the barrels up as much as blank, then I'm RTF out of er anyway... 

just remember the feeling in my gut knowing that I'd switched barrels, and needed to do it again, but the first hadn't cooled enough =) though when fighting an enemy that doesn't die... I suppose that happens.

 

[KevinB]

blanks ammo powder burns hotter/quicker with ahigher pressure spike than live ammo -- hence why the throats get burned out quicker on weapons that get more blank use (and some people stupiduty with blank fire control)  -- however live ammo is sending a round thru the barrel which also caused friction -- live barrels get hotter throughout their length with live ammo than ball.

Yes miniguns require power - but the source that holds the vast ammount of ammo usually has power 
  Some have selective rates of fire - all FAST to REALLY FRICKEN FAST

 

[NATO Boy]

perhaps cost is the answer?

A fluted barrel looks more complex to manufacture; thus more expensive......other than that, I don't see why fluting isn't incorporated in our barrels.

Kev?

 

[KevinB]

YUP - the cost issue bites again..

However LAV barrels are fluted, some sniper rifles, and some other project gun stuff.

A fluted barrel gets more surface area thus can cool at a greater rate (all else beign even)  - it is lighter than a barrel of the same outside diameter - yet more rigid than a barrel of the same weight with a standard diameter.

Fluting must be done during a certain portion of the manufacturing process after the barrel has been stress relieved (IIRC) or else it can ruin the barrel.

 

[kato]

Cooling fins were in vouge in the eaily days of air cooled MG's, it was found however that unless there was a constant air flow ie. on an aircraft , there was no appiciable benifit and the cost of manufacture was prohibitive .Fluted barrels are more for wieght saving than increased surface area.Just as a nice to know the early FN MAG 58 had cooling fins (the last GPMG to do so ) and the early PKM had fluting . Both went to plain barrels as a cost saving measure .

Out Kato

 

[vonGarvin]

Short answer: you have a quick change barrel on the C9/C6 family of weapons, so the idea is that you fire off two belts and then change barrels in about 3.5 seconds.  Fire two more belts, and change again (to the third barrel in the case of the C6, back to the first barrel, if hand cool, on the C9).  If you need to fire more than 800 rounds out of a C9 in bursts, even rapid, that is 8 minutes of fire, give or take.  In the four minutes, depending on the ambiant temperature, the barrel "may" be cool enough.  But, if you could imagine such a situation in which 800 rounds in 8 minutes are required, and you haven't been shot yet, well, just keep firing and let the techs worry about the barrel later.  Besides, if that's the situation, there will be plenty of other, less-used C9s lying around anyway ;-)

 

[geo]

VonG... 50s also got the quick change barrel system.... which beat the hell outa having to mess around with the headspace adjustment.