What you need to know about the Army's new gun

What you need to know about the Army's replacement for the M9 Barretta.

Firearms manufacturer Glock has filed a protest with the government over the Army's award of a new pistol contract to competitor Sig Sauer, according to documents filedwith the Government Accountability Office on Friday.

The move complicates but does not put on hold the Army's plans to begin testing its XM17 Modular Handgun System, officials said.

"Glock received a debriefing concerning why they did not receive an award on Feb. 17," the Army said in a statement. "Glock's protest to the GAO is timely but was not filed within five days of receiving their debriefing, meaning that under the Competition in Contracting Act, Sig Sauer can continue contract performance during the pendency of the protest."

Meanwhile, Army Materiel Command's protest litigation branch is defending against Glock's protest, the Army statement said.

The Army announced in January that it would replace the M9 Beretta, soldiers' sidearm for more than 30 years, with a modified Sig Sauer P320.

Sig Sauer released the P320 in 2014; it is a polymer striker-fired pistol that has interchangeable grip modules that can also be adjusted in frame size and caliber by the user. And while the weapon can be adapted to shoot 9mm, .357 SIG and .40 S&W ammunition, the Army is opting to stick with the 9mm.

The service first announced the competition for the new pistol back in 2011. Sig Sauer beat out Glock as well as Smith & Wesson for the up-to-$580 million contract, which includes weapons, accessories and ammunition to be delivered over a period of 10 years.

A decision from the GAO is expected by June 5, Army officials said.