The service's Life Cycle Management Center's Small Arms Program Office plans to complete fielding of the M18 9mm pistol by August 2022, according to an Air Force news release.
The $22.1 million deal with Sig Sauer includes test ammunition and engineering services, according to the release.
The Army awarded Sig Sauer a contract worth up to $580 million in early 2017 after the company beat out Glock Inc., FN America and Beretta USA, maker of the current M9 9mm service pistol, in the MHS competition.
The 10-year agreement calls for Sig to supply the Army, and other services, with full-size M17 and compact M18 versions of the striker-fired 9mm pistol.
The new pistols can be outfitted with suppressors and come with Tritium sights for low-light conditions, as well as 17- and 21-round magazines.
The Air Force chose the more compact M18 MHS to replace the full-size M9.
"The Air Force bought the M9s back in the 1980s, and the design has not really changed since then," Merrill Adkison, Small Arms Program Office senior logistics manager, said in the release. "M9s are larger, heavier, all-metal pistols; whereas M18s are lighter polymer pistols with a more consistent trigger pull and adjustable grips for large and small hands."
The new sidearms are also a lot less expensive, according to the release, which adds that a new M18 costs the Air Force about one-third of what it would cost to buy an M9 today.
"It is important for the U.S. Air Force to move forward with improvement and replacement of weapon systems to keep pace with potential adversaries and field the best technology and equipment available for our warfighters," Brian Lautzenheiser, lead program manager in the Small Arms Program Office, said in the release.
-- Matthew Cox can be reached at firstname.lastname@example.org.