I’ve had to do some research into possible near-future weapons systems for a couple of series, now. If you’ve read The Colonel Has A Plan, you might have noticed that the Marines under Colonel John Brannigan are using M27s and LSAT machineguns instead of the current M4s and M249s or M240s. Similarly, the Marines at Camp David in Lex Talionis are armed with M27s. Now, arming Marines with M27s is an easy choice, since the Marine Corps recently announced a wider deployment of the glorified HK 416s, but it touches on a common theme when writing near-future military fiction. Including new weapons and gear that isn’t necessarily in common use yet helps to establish your setting.