An advantage of the M4, or any AR-type platform, is its versatility: by popping the two take-down pins, the user can trade upper receivers in seconds. Early on in Afghanistan, there were very few of us that had any real combat experience and our tactics were changing day by day to adapt to the threat. During those early days and in subsequent deployments to Iraq, the learning curve was steep. We fine-tuned our kit to meet the mission and the modularity of the M4 helped us do just that.
The private sector firearms industry responded to the Global War on Terror with innovation and dedication, providing the military with products that allowed us to constantly maintain a technical edge over the enemy. The Picatinny rail equipped flat top receivers and forends on our M4s meant that we could easily mount whatever optic, light, laser, grip or other accessory that the mission demanded. Since we often ran missions at night to maximize the advantage of our night vision technology, our weapons were equipped with an ATPIAL/PEQ-15, a device about the size of an old cassette tape. This device can be used to project a visible laser onto the target in addition to an infrared laser/illuminator that is only visible with NODs.
If a mission was likely to be CQB-oriented or we would be traveling in vehicles, I could mount a 10.3”-barreled upper with either an EOTECH or Aimpont red dot optic. These uppers were built at Naval Surface Warfare Center, Crane Division in Indiana, aka “Crane”. The ten-inch configuration is called a MK18. If I thought I might need more reach, I could use a 14.5” upper with a magnified Trijicon ACOG, which I used in-conjunction with a small red dot optic in case we had to fight our way through a building or other tight space in order to get to a target or reach an overwatch positon. A third upper might be equipped with an M203 40mm grenade launcher. The KAC sound suppressors we were issued reduced the sound of the rifle’s report and helped eliminate muzzle flashes, though they don’t suppress sound nearly as well as they do in the movies. And, when you and a handful of your best friends are firing rifles inside the same small room, a suppressor is a really nice thing to have.