Board Thread:Forum Games/@comment-31503594-20171013121527/@comment-30868172-20171013184621

An extensive maintenance program intended to extend the service lives of M249s has been carried out to refurbish rifles, especially units that suffered from wear due to heavy use. In particular the warping of the receiver rails on the early-models was a defect that occurred in heavily used first-generation M249s. This defect however has been completely eliminated on later models and is no longer present on the current-issue M249, which has reinforced rails and full-length welding rather than spot welding. Also being worked on is replacement of the M249's buttstock with a redesigned adjustable stock.[49]

The U.S. Marine Corps tested the M27 Infantry Automatic Rifle, a lighter, magazine-fed rifle to supplement and partially replace the M249. With plans to buy up to 4,100 IARs to complement and partially replace its 10,000 M249s (of which 8,000 will remain in service) held at platoon level,[50]  it acquired 450 of the Heckler & Koch HK416–based weapons for testing.[5]  The Marines started fielding the M27 in 2010, but kept both weapons in the inventory due to the M249's greater ammunition capacity and higher sustained fire rate; rifle companies are typically issued 27 IARs and six SAWs.[51]  The U.S. Army does not plan to introduce the IAR. Colonel Robert Radcliffe of the U.S. Army Infantry Research and Development Center stated that an automatic rifle with a magazine would lower the effectiveness and firepower of a squad. While the Marine Corps has 13-man squads, the Army organizes its soldiers into squads of nine and needs considerably more firepower from the squad machine gunners to make up the difference. The U.S. Army does, however, want to replace aging M249s with newer weapons.[50]