GM is making parts for Patriot missiles now

America's biggest carmaker is building for the US military. credit should read BULENT KILIC/AFP via Getty Images GM is now making housing components for Patriot missile interceptors.

It delivered the first batch just 22 days after signing a contract with Lockheed Martin.

GM expects its defense subsidiary to generate nearly $700 million this year.

General Motors is adding missile parts to its manufacturing résumé.

On Thursday, major defense contractor Lockheed Martin announced that GM Defense — the automaker's military subsidiary — had delivered housing components for the PAC-3 Missile Segment Enhancement interceptor, a missile used by the Patriot air-defense system.

The companies entered into a formal contract on August 6, and the first batch of components was delivered to Lockheed 22 days later, the companies said.

Tim Cahill, Lockheed Martin's president of missiles and fire control, called it an "extraordinary 22‑day turnaround." Demand for Patriot interceptors, particularly the advanced PAC-3 MSE built for complex threats, has surged as the wars in Ukraine and against Iran strain US and allied inventories.

Over recent months, media reports and think tank assessments have raised concerns about US munition stockpiles, including Tomahawk land-attack cruise missiles and Patriot interceptors .

The Pentagon and the White House have dismissed concerns about the status of the US stockpiles.

A newly released Department of Defense Inspector General report said that " munitions expenditure in [Operation Epic Fury] has resulted in strategic inventory shortfalls and revealed industrial base bottlenecks for munitions resupply." It did not specify which kinds of munitions.

The US defense industry is also expanding munition production in partnership with the Pentagon.

GM isn't building the entire interceptor.

Still, its component production marks a notable expansion for a defense business better known for military vehicles.

During a July earnings call, Mary Barra, the automaker's CEO, called defense a "growth business" and said the company was targeting nearly $700 million in defense revenue this year.