I find it odd that the need and time to continuously reload the magazine feed M27 isn't mentioned, compared to that of a belt feed LMG...I truly thought this operational short coming was inherently identified with performance and the replacement of the BAR in U.S. service.
It's not that clear-cut. A magazine-fed gun does need to be reloaded more often but it can be reploaded rather quickly. A belt-fed gun doesn't need to reload as often but takes quite awhile to reload when it does. If you are firing from an emplaced position with an assistant who can keep making up the belt before it runs out (or at least prep the reload belts) that's one thing, but for a solo gunner on the assault, the actual gun uptime might be better with magazines -- especially if you go for something like a 60-round drum for the initial loadout followed by 30- or 40-round magazines for reloads. And the gun will be a lot easier to handle without a 200-round belt hanging off it. So if you are using the gun as a base of fire, yes, you probably want a belt. As a support gun in the assault, you may well want a magazine. So in a perfect world, you maybe want magazine-fed automatic rifles in the infantry platoon's rifle squads and a couple of belt-fed GPMGs in the platoon's weapons squad.
The Marines were looking at a drum for the IAR fairly recently.
The Marine Corps has been reportedly testing a new high-capacity magazine for infantrymen carrying the M27 IAR.
www.militarytimes.com