An M4 went missing during a training event at Fort A.P. Hill in Virginia "between mid-February and mid-March," according to Christopher Grey, a CID spokesman.
It's unclear why CID officials will not disclose the specific date the rifle went missing. They also did not respond when asked about the unit responsible, or whether the rifle was equipped with optics or additional attachments.
Politico first reported the news Thursday.
It's common for M4s to be equipped with an advanced combat optical gunsight, or ACOG, which greatly enhances the shooter's ability to hit targets from a long distance. M4s also can be equipped with an M68 close combat optic, a red dot sight with no magnification.
The Army regularly equips M4s with infrared lasers, which can be seen only with night vision goggles. The laser allows the shooter to easily engage targets at night. Units also arm some of their rifles with an M320 grenade launcher.
When a soldier is assigned a weapon, their leadership is typically tasked with conducting regular checks to make sure they are still in possession of it.
A lost weapon is a serious incident in the military that could potentially end the career of the soldier the weapon was assigned to and have a ripple effect through the chain of command. In 2019, 3rd Battalion, 6th Marines, lost two rifles at Camp Lejeune, North Carolina; the battalion commander and sergeant major were fired.
Roughly 27,000 National Guard troops deployed to Washington, D.C., following the Jan. 6 pro-Trump mob assault on the U.S. Capitol. About 2,300 Guardsmen are set to protect the Capitol through at least May.
Troops from Hawaii, Illinois, Indiana, Kentucky, Massachusetts, Missouri, Oregon, Washington, Wisconsin, the District of Columbia, Delaware and New Jersey continue to stay on the mission, according to the National Guard Bureau.
Law enforcement has not specified any ongoing threats, and the mission has grown deeply unpopular on Capitol Hill, with bipartisan calls from lawmakers for the Guard to end its mission.
-- Steve Beynon can be reached at Steve.Beynon@military.com. Follow him on Twitter @StevenBeynon.