Another CoD classic, once it was called the M249 is now the Bruen Mk9. This light machine gun is configurable to any tactical application, with different handguards, barrel and stock options. Being a light machine gun, it has two sizes of box magazine and like the typical M249, has options to load in STANAG magazines. The quirk of using this machinegun in modul form is the ability to swap to .300 BLK, however due to the limitation, it only applies to the magazine, not the box mag, thus the box mag also comes included with .300 BLK options, for those sneaky types.
The stock options also allows you to extend your modularity to include Meat's and NotWolfie's AR2+ plus stock options. So go ham.
Model from Call of Duty MW3