The Marine Corps and the Army use different rifle ammo -- and Congress is demanding a report explaining why.
The final joint version of the Fiscal 2017 National Defense Appropriations Act, released Wednesday, includes a provision requiring the secretary of defense to submit a report to the House and Senate Armed Services Committees explaining why the two services are using different types of 5.56 mm ammunition for their M16A4 and M4 rifles.
According to the provision, the report must be submitted within 180 days after the bill, which includes the entire defense budget for the coming year, is enacted.
If the secretary of defense does not determine that an "emergency" requires the Army and Marine Corps to use the two different types of rifle ammo, they must begin using one standard kind within a year after the bill is passed, it states.
This provision, introduced by the House of Representatives, addresses a longstanding difference in procurement strategies between the two services. The Marine Corps uses an M855 5.56 mm round, while the Army uses the M855A1. The Army moved away from the M855 in 2010 after finding that the M855A1 steel-and-copper round performed better. The Marine Corps planned to do the same, but the project was sidetracked in 2009 when some bullets did not follow their trajectory in testing.
In 2015, Marine Brig. Gen. Joseph Shrader, then commanding general of Marine Corps Systems Command, told a congressional panel there were plans to test the M855A1 rounds again.
"What we are pursuing in a new round … are three things -- precision, lethality and reduced signature or muzzle suppression," he said.