The combat-tested M4 carbine will remain in soldiers’ hands for a while even as the service develops a new, next-generation weapon as one of its top modernization priorities.

The Next-Generation Squad Weapon, a key part of the Soldier Lethality Cross-Functional Team’s portfolio, is undergoing “rapid prototyping right now,” said Douglas Bush, acting assistant Army secretary for acquisition, logistics and technology.

But initial plans call for the weapons to be fielded only to the Army’s close-combat force and those who directly support them—about 120,000 infantry, cavalry scouts, combat engineers, forward observers and medics, as well as special operations soldiers.

“We have not considered yet whether we’ll replace the M4 and M16,” said Gen. Mike Murray, commander of Army Futures Command. “That is a future decision to be made, very much to be made based on what we find with the prototyping going on right now.”

Ultimately, the Next-Generation Squad Weapon will feature two rifles—one to replace the M4 and the other to replace the M249 Squad Automatic Weapon. The two rifles, along with new 6.8 mm ammunition, will give dismounted combat troops increased lethality, officials have said.

Three vendors are in the running to produce the weapons, and the Army plans to select one vendor for rapid fielding and initial production during the first quarter of fiscal 2022, Bush said.