Orbital ATK has won orders with a combined value of $210m to produce small-calibre ammunition for the US Army.
The company will manufacture 50-calibre, 5.56mm and 7.62mm ammunition at the Lake City plant in Independence, Missouri, US.
Orbital ATK small-calibre systems division vice-president Kent Holiday said: "This latest order continues a long history of supplying only the best ammunition to our warfighters.
"Every round is produced with the highest quality because we know that those defending freedom depend upon the good work of our employees."
Since opening in 2000, the Lake City plant has produced nearly 15 billion rounds of small-calibre ammunition for US and allied warfighters worldwide.
In the past several months, Orbital ATK and the US Army have been investing in new technology to enhance the facility's efficiency and cost-effectiveness.
Orbital ATK's defence systems group provides weapons, advanced propulsion and hypersonics, and missile components for air, sea and land-based systems, as well as ammunition and related products.
The company recently secured a contract to support the US Department of Defense's (DoD) non-US standard ammunition (NSA) programme.
Under the terms of the $20m contract, the company will supply non-standard ammunition and mortar weapon systems to unidentified international allies over a five-year period.
The contract follows a previously awarded NSA contract that expired in December 2015.
Orbital ATK has delivered approximately 600 million NSA products to US allies since the programme begun in 2008.