The biggest news in military circles this week, apart from the war going on in Ukraine, is the selection of SIG Sauer’s MCX-Spear and SIG-LMG as the U.S. Army’s NGSWs to be called the XM5 and XM250. These will replace the M4 and M249 and will be using the 6.8mm round.

Whilst it is big thing that the U.S. Army is moving on from the 5.56mm round, it may take sometime before the soldiers will be fully issued with the rifles due to ammo availability.

As reported by Task & Purpose, in a press conference at the Pentagon last Wednesday, Army Brigadier General Brig. Gen. Larry Burris Jr., director of the Future Soldier Lethality Cross Functional Team, told reporters that it will be take years given that the U.S. Army will still need to build the facility that will produce ammunition that will be required by tens of thousands soldiers in order to use the NGSWs.

SIG XM5 NGSW (MCX-Spear)

Burris said that, “The fielding of the weapon is based upon ammunition production. What we don’t want to do is field capability to a unit where we don’t have training ammunition or contingency ammunition if required.”

The U.S. Army will be procuring 107,000 XM5s and 13,000 XM250s for those who are in active duty as well as those in the National Guard. With new ammo being introduced after over 60 years of using the 5.56mm with the M16, M4 and the M249, transitioning cannot happen overnight and is expected that it will take years to fully equip the soldier especially with the need to build up the ammo production capability.

For the meantime, they have no plans to reduce production of the 5.56mm and 7.62mm NATO rounds used in the present firearms.

Whilst the U.S. Army is building up its 6.8mm ammo production facility which is expected to be open in 2026, SIG Sauer will be producing the rounds needed. The U.S. Army production facility will be built at the Lake City Army Ammunition Plant in Independence, Missouri and SIG Sauer will play a backup role once the facility is fully online.

SIG XM250 NGSW (SIG-LMG)

The 6.8mm round, when fired, fly in supersonic speeds much longer the 5.56mm round which makes them more accurate. When compared to the 7.62mm round it is more controllable allowing soldiers to effectively engage targets between 500 to 600 metres. But the main consideration by the U.S. Army in selecting the 6.8mm round as the new ammo is the requirement that the new around can penetrate body armour that is being used by potential enemies.

It was not mentioned at the press conference if it can penetrate Level IV body armour which is issued to U.S. soldiers.

All in all, the M4s and M249s won’t be fully replaced and it would probably take a decade for these to be fully phased out.