Since Wikipedia usually says it best, I’m just going to provide their overview on light machine guns here:
“A light machine gun or LMG is a machine gun designed to be carried and fired by an individual soldier, with or without an assistant, and used in a front-line infantry support role. LMGs are often used as squad automatic weapons, or SAWs.
An LMG may be identified either by the weapon or by its tactical role. It is used to fire in short bursts, usually from a bipod: a sustained-fire mount such as a tripod is a characteristic of a medium machine gun. Some machine guns – notably general purpose machine guns – may be deployed as either an LMG or a medium machine gun. As a general rule, if a machine gun is deployed with a bipod it is an LMG; if deployed on a tripod it is a medium machine gun – unless it has a caliber of about 10mm or larger, making it a heavy machine gun. Modern LMGs often fire smaller-caliber cartridges than medium machine guns, and are usually lighter and more compact.”
There are a few points that I need to touch on in regards to running a light machine gun on the airsoft field. Do NOT let the word, “light” fool you. There is nothing light when it comes to the actual weight of the gun. You’re looking at 20+ lbs of weapon that you’ve got to deal with. Not mention, the extra BBs you’ll need to have on your person in the event you drain your box mag in the middle of a game and can’t run back to the parking lot for more. And when I say, “extra,” I’m not talking about one or two hundred extra. I’m talking another several thousand extra. At least enough to refill your 1,500 to 2,500 round box mag. Doesn’t sound like a whole lot, but believe me, when you’ve already got too much stuff loaded into your Tac Vest and/or battle belt, a couple extra thousand BBs WILL be noticeable.
Additionally, a good friend of mine in the United States Army advised me that box mags are referred to as “nut sacks.” Just a little droplet of wisdom for ya.
Another factor to consider when purchasing a light machine gun is cost. Not just the cost to acquire the rifle, but overall cost of operating and maintaining it. Your job as an LMG operator is to run your weapon on full auto and put a lot of rounds down range in an effort to keep your enemy’s head(s) down. This will allow your squad mates to advance upon their “pos” (position) with less resistance and greater ease. Running any airsoft rifle on full auto will increase the wear and tear on the internals in general, but especially the piston. Plan on your piston getting stripped on a frequent basis. If you’re less fortunate, your gears or motor will get torn up and will need to be replaced. I say less fortunate because replacing gears and/or a motor is much more expensive than just swapping out a $20-$30 piston. Speaking of the frequency of piston replacements, one of the nice things about running a Classic Army M249 SAW is that the designers seemingly anticipated this issue and made it extremely easy to swap out the piston without having to disassemble the entire gearbox like you would have to do with just about any other rifle. I may be mistaken, but I feel like the A&K version may also have a similar feature like this. Another element of the overall cost is ammunition. You’ll be blowing through BBs like there’s no tomorrow. You’ll run out of BBs quicker than you would running a semi-auto assault rifle or especially a bolt-action sniper rifle, and therefore you’ll have to purchase more, thereby increasing the overall cost to run the light machine gun. Depending on whether you’ve got a tightbore barrel installed or not, should determine the quality of BB that you run through your gun. If you’ve just got a stock level barrel, with an inner diameter of 6.04mm or more, then you can probably get away with running cheaper BBs, like those found at WalMart. However, if you’ve got that TBB in your LMG, you’re not going to be running Crossman BBs through there. You’ll need to purchase some semi-decent quality BBs to avoid jams in the inner barrel. If you’re thinking better quality BBs equals higher operating cost, then you’re just so darn right I can’t even begin to describe.
NOW, don’t get me wrong and think that I’m advising AGAINST running this role. Because that is certainly not the case. Running an LMG is a barrel of fun AND a bag of Kettle Chips! Let me tell you. However, in the essence of full disclosure, I wanted to let those of you that didn’t already know, that the reality of running a SAW is a bit less glamorous than perhaps perceived. I just wanted to let you know what you’d be getting into ahead of time, rather than let you bite the bullet and find it all out the hard way on your own.
So the bottom line when it comes to light machine guns is this: be prepared for three things, including but not limited to, spending more money than an assault rifle to operate it, dealing with the massive weight load and to have an incredible time hosing down any tango(s) that stands in your way of the objective.
Let us now discuss a few of the common LMG variants you might see on the field.