Marines participating in Operation Phantom Fury in 2004 engage insurgent fighters with M240B Medium Machine Guns. This is why your machine gunner friend is always asking you to repeat yourself.
Let's answer a few of the more common questions about this video. First, no, there's almost no chance anyone inside of this room is wearing ear protection. In 2004, Marines were issued small foamy ear protectors that when inserted soaked up sweat and were incredibly uncomfortable. Not only were they uncomfortable, they provided almost no hearing protection whatsoever, so people normally just didn't bother to pop them in, even when in a situation like this one.
Second, yes I realize there is a guy with a paint brush on his flak jacket. No, he is not planning to do arts and crafts in the room. The paint brush is an important tool for every medium machine gunner. It helps to keep the dust off of the machine guns when they are dry, and they can be used to apply a liberal amount of CLP to the weapon which keeps it running more efficiently over a longer period of time. It's not a piece of SL3 that is issued, it's just something machine gunners carry.
Allegedly, these are Marines from Marines from the Weapons Platoon of Echo Company, 2nd Bn, 1st Marine Regiment, 1st Marine Division. We can't confirm that however. If you were a Marine from Echo Company 2/1 during Operation Phantom Fury, let us know if you recognize any of these guys.