Why don't modern LMGs have a barrel change system that would

>>30342342
I will confess I have wondered this too. I would further add it would make sense to add large cooling fins to a heavy barrel.

>>30342342
Unnecessarily logistic complication

>>30342361
Don't most LMG Gunners/LMG Gunner Assistants carry an extra barrel or two around at all times anyway?

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>>30342342
Generally speaking a light barrel is not advisable on a squad level machine gun or automatic weapon.

Let the rifles do the talking if you are firing on the move and your gunners do the hosing down when it's time to put some heads down.

The M27 strikes a balance. Before that I think the Stoner LMG is the last time we saw a machine gun really fill a run and gun roll for shooting on the move.

>>30342342
Well, for one thing, you or your AG would still be stuck carrying your heavy barrel(s) while moving around. Another thing to consider is that the 240 and 249 both have short barrels issued along with the standard length. The exact protocols for using the different barrels varies by unit.

>>30342367
Two kind of barrel configuration is the logistic complication I'm talking about.
Not necessary. It's far easier to make grunt carry more weight.

>>30342372
> This. It all comes down to unit TTP's.

>>30342342
You could do that with just about every LMG with changeable barrels (like the M60 pictured), but then you have the complication of vastly different ballistics. It's far easier for one sight to be used for two different barrels if the barrels are as identical as possible.

Then there's the fact that the reason why you use two barrels is for cooling, and that a heavy barrel will overheat only slightly slower than a lighter one, and if you don't have an extra heavy barrel then you have to go to the lighter one anyways. And if you're carrying two light and two heavy barrels, you're suddenly heavy and clunky as fuck.

>>30342367
They do, but of the same type, due to the sights and the weight.

And a short barrel M60 (like the one pictured) has no trouble hitting targets at 600m.

>>30342368
>the M27 strikes a balance
...no?

It's a closed bolt, 30rd-mag-fed rifle. It is the quintessential assault rifle, not an LMG.
>the open-bolt-for-auto thing never happened
>the >30rd mags never happened, they're cucked into STANAGs
It's literally a piston-driven, slightly heavier barreled AR and they'd have been just as well off with M4A1's since those do better at reducing muzzle climb anyway so they're actually more useful on full retard.

>>30342367
Generally no, at least not in the US infantry.

That shit died in the late 90's with the advent of the para-SAW and its shorter barrel.

m240 teams might carry an extra barrel, but even then it usually stays on the trucks.

>>30342342
Because when we want light, we also want compact, and the easiest way to achieve both is to use a short but thick barrel.
>stiffer
>still decent cooling
>shorter
>lighter

What I don't understand is why we don't use fluted barrels. Less weight and extra cooling while retaining most of the stiffness seems like a good thing all around.

>>30342528
Didn't realize neither the open bolt nor the >30rd capacity never made its way into service. In that case it's not providing much that the squad doesn't already have at its disposal.

Main point of my post was that taking an LMG at the squad level and throwing a lightweight barrel on it is not a good idea.

>>30342545
Sure it is.

We really don't do emplaced fighting positions any more, it's literally 100% maneuver warfare and we will always be on the offensive.

M240, M60, PKP, MG3, guns of these size are not LMGs.

OCD aside your "barrels" are light. A 240 barrel is literally a fraction of the weapons weight. Which brings me to point number 2.

SAWs are a squad/section level weapon that already move up with said infantry for its mobile use. MMG/GPMGs, the heavy guns, 240, M60 etc work at a higher level with different deoyment where "firing on the move" serves almost no purpose for how the guns are used.

>>30342547
>we will always be on the offensive.
During GWOT a large percentage of the fighting took place repelling jabs and attacks from entrenched and fortified positions. Even when we were on the offensive.

>100% maneuver warfare
Which still requires MGs to be used when the violence of action is needed. You don't want a lightweight barrel on a gun firing 100-500 rounds of 5.56 or 7.62 in bursts, in a single contact. That's all I'm saying.

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>>30342572
Depends on the country in question. In Denmark we use two short barreled M60E6s (pic related) per infantry squad.

>>30342590
please put that poor pig out of its misery

>>30342581
>during GWOT a large percentage...
Less than 1% of all engagements. So no, not even remotely. They just made the news a lot.

>which still requires MG's to be used...
Your LMG's are at the squad level, they move with the squad, and are almost always fired from improvised firing positions (convenient wall, plain ol' prone, hood of a car, etc) at relatively close ranges (<400m) to where you will see no appreciable difference in accuracy/effect on target from a longer or heavier barrel.

Most of the time your GPMG's (.30cals) and all of the time your HMG's (.50/14.5mm) will be pintle-mounted on a vehicle, where weight doesn't much matter and they generally have heavy(er) barrels anyway. The rest of the time you have a 3-5 man team crewing your GPMG.

>>30342590
That's cool as fuck, Denmark.

>>30342605
The heavier barrel will be able to sustain a much greater amount of ammunition expelled before affecting accuracy, and later, breaking. Light barrels wear down way, way too fast.

>>30342605
>Less than 1%
Where exactly are you getting that stat. A metric fuckload of our offensive operations involved setting up an OP or multiple OPs in wild country, prodding with community outreach and combat patrols and mowing them down and dropping bombs on them when they got a gaggle of idiots together to attack.

>>30342350
>I would further add it would make sense to add large cooling fins to a heavy barrel.
Not sure about fins, you don't want them to bend in transport, but fluting at least. But that costs money that the mil doesn't want to spend.

>>30342528
Lol, it's a backdoor M4 replacement.

>>30342628
It's an acceptable tradeoff for something carried as much as it is.

>>30342630
The whole "combat patrol" thing. For every time an OP was attacked there were about 170 "combat patrol" engagements.

>>30342630
I know this is anecdotal, but I was in Iraq from July 05 to September 06.

My squad got shot at literally every single patrol. Sometimes 2-3x a patrol. That's around 400-450 different engagements while on patrol.

Meanwhile, not counting mortar attacks, our COP got attacked exactly 0 times.

Then I was in Afghanistan from Dec 07 to Dec 08. My squad got shot at about every third patrol. That's, let's say, 120 engagements. Our COP got attacked (including mortars) exactly 1 time, but it was a big'un.

So over 2 deployments that's a ratio of 520-570:1, or roughly 1/5th of 1% of the time we were fighting from a prepared position.

So unless you want to count things like the daily mortar strikes from the back of a moving ambulance that managed to land 1 mortar within the humongous cantonment area of a megaFOB like Diamondback, Speicher, the ~100 square miles of the Green Zone, etc as an actual attack, I think >>30342605 is probably correct. Might maybe, MAYBE be as high as 5% in Afghanistan, but still a very very small percentage of engagements.

>>30342342
>let's make this gun less capable of doing what it was designed to do

>>30342667
And in those engagements how were squad automatic weapons and LMGs used? Generally speaking the machine guns put in the most work when people dug their heels in. They suck to carry around but I would not want a lightweight barrel on a 249 or 240 when putting multiple belts through the gun. Groups open up even larger than they are and barrels would wear out pretty quick.

I would be interested to see how a fluted barrel would fare in testing on machine guns like anon above suggests.

>>30342659
Bent fins is better than no fins.

>>30342721
...have you ever even been around, much less in, a Western military?

Here's how they're used
>you're on patrol
>someone starts shooting at you
>you're not sure from where, because urban/the middle of nowhere with tons of cover
>grab nearest piece of cover yourself (either a car or a rock)
>flop bipod open
>flop LMG on car or rock
>fire a few bursts in the general direction you *think* the shooting's coming from
>by this point 99% of the time whoever shot at you either fucked off or got drilled by your SDM, because it was a single guy with an AK who was either >500m away and lobbing them kinda-sorta in your general direction from the hip, or a guy in a window ~50m away that fired like 6 rounds, ditched the rifle, and ducked out because he didn't wanna die pointlessly after he realized he didn't hit shit.

I don't know what you think combat was like in the GWOT, but clearly you're misinformed.

>>30342342
SAWs do. Dudes usually carry one or the other though

>>30342721
that whole animal mother shit doesn't really happen anymore anon.
yeah, it has happened. rarely.
is it an everyday thing? hell fucking no

>>30342721
This guy again: >>30342708
Our SAW gunner shot less than 2000 rounds total in my first deployment. Overheating was a total nonissue.

Second deployment our SAW gunner fired less than 1000 rounds total. Again, overheating was a total nonissue. The one time the COP got attacked everyone got on a truck and used either the GPMG's or AGL's or HMG's. Nobody was on a SAW, nobody was on a rifle. Needless to say, we won. The US, at least, has the logistics to be able to do that in most places.
>single platoon in a HESCO fort outside a goatherder's village in the foothills in Afghanistan
>1.2 gun trucks for every person on the COP because they broke down a lot and we didn't have mechanics there most of the time (they'd make a circuit of the COPs and would be at each one about once every 3 weeks for all of about 2-3 days depending on how broke shit was)

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>>30342735
>Top kek
Very concise

>>30342659
Fluting does nothing for heat management, it adds very little surface area.

>>30342905
It does increase cooling, but it does so by exposing metal that is closer to the bore, not by increased surface area

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When I fist heard of the semi auto saw I thought it was fucking dumb. After seeing MAC review his, now I fucking want one.

>>30342590
Danes have good taste. Aesthetically at least.

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>>30342350
>it would make sense to add large cooling fins to a heavy barrel.
which is why not a single modern light, medium or heavy machine gun uses them
because it just makes so goddamn much sense to add them

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The Canuck C9A2 comes with a regular barrel and a short barrel.

>itt: niggers don't know about the HK 121 I

ishygddt