Finally, I've gotten myself into more than just being an Assault class. I've picked up being a Support in some cases, and have made myself quite familiar with the Support Class's LMGs. So, let's take a little time to talk about these weapons.
The M27 is an M416 with a longer barrel and bigger magazine. This does not mean it behaves at all like an assault rifle. You could use it like one, yes, but this weapon is heavier, and you should not expect it to behave like an assault rifle. But, when using as a support weapon for suppressive fire and gunning down baddies at range, this weapon is very good at that. Its downfall is the small magazine. It does reload pretty fast, though.
As my friend Aerobon will happily attest to, the RPK is a beast. It is, like the M27, a larger version of an assault rifle. This time, it's a AK-74M with a longer barrel and bigger magazine. It handles much like the M27, from what I can tell. Whatever the difference is, it's subtle.
The first belt fed LMG you get is the M249. It fires the same bullet as assault rifles, the 5.56x45mm NATO. The big deal is that it's a fucking belt fed LMG. While it has the same damage as assault rifles, it has a 100 round belt and comes with a free bi-pod. It fires at 800 rounds per minute, so getting enough shots on target to kill is hardly an issue. This weapon, with the light round, is best suited for close to medium-long range combat.
This LMG is your first full power LMG. Instead of using an intermediate round, the PKP fires the full power 7.62x54mm R. This gives the PKP more range and more stopping power. But, with it's full power range, it fires slower at 600 rpm. The slower fire rate is barely a problem, because it will actually help prevent emptying the belt. This thing was built for long range saturation. Stick a bi-pod on and a 3.4x scope.
The M240B, or, as I call it, the 240 Bravo, is the answer to your prayers. It fits nicely in the gap between the PKP and M249 by using the heavy 7.62x51mm NATO, but by also having a faster fire rate of 650 rpm. This weapon is designed for long range saturation and corridor locking. Set yourself up in a narrow passage and people will be dropping into piles.
The M60 here is all about precision. When on a bipod, this thing will put rounds on target, at full auto, at crazy ranges. It fires the same 7.62x51mm NATO as the 240 Bravo, but at a slower rate of 580 rpm. This, in my experience, is offset with the control and accuracy of the M60. If you need to put rounds down range, at range, the M60 is the way to go.
This weapon is a weak M60. It fires the Chinese intermediate round, the 5.8mm DAP-87. This gives it the weaker damage of the assault rifle round LMGs, but it also has the control and low 580 rpm fire rate as the M60. It does not have the same long range accuracy, though. The role this weapon is designed to fill is for suppressive fire. The lower fire rate helps conserve ammo when unloading the weapon at enemies. Use an extended magazine; you won't regret it.
This is another Chinese machine gun. It uses the same round as the Type 88, but this time it comes in a drum fed magazine. The magazine makes it reload much faster compared to other LMGs, while still offering the same potential saturation. The magazine is only 75 rounds, compared to the belt fed weapons using 100 round belts. This is rarely a problem, however. 75 rounds is pretty large. You don't get a whole lot of ammo, though, so resupply yourself often.
They killed my baby. This thing is not like how it was in Bad Company 2 at all. But that doesn't mean it's bad. The MG36 is fitted with a 50 round beta-C mag, so it fits itself as an assault rifle feeling weapon. But, unlike the other LMGs, you could honestly get away with using the MG36 as if it was an assault rifle.
This is a laser on a bi-pod. It's a crappy laser off the bipod but that's no the point. Recoil on this bad boy adds up quick, but you can squeeze off a 10 shot burst without suffering too much. If you're not a huge fan of being trapped on a bi-pod, give this thing a go.
In real life land, the LSAT is supposed to be the Light Small Arms Technology. It uses plastic casings with a plastic belt in a box made of rigid cloth. The barrel is short and it has no shroud. The entire thing, ammo and all, weighs 40% less than a traditional LSW or SAW with metal. But, in game land, the weapon is low on recoil and high on lasers. The spread is not that tight, but it doesn't get much bigger unless you jump around while shooting. You can use this weapon as a stationary shooter or get close to spray them in the face.