Rock-Ola became a prime contractor for production of the M1 carbine for the US Military during World War II. Rock-Ola machined receivers, barrels, bolts, firing pins, extractors, triggers, trigger housings, sears, operating slides, gas cylinders, and recoil plates. Rock-Ola used its furniture machinery to manufacture stocks and handguards for its own production and for other prime contractors, and subcontracted production of other machined parts. Rock-Ola delivered 228,500 military carbines at $58 each before contracts were cancelled on May 31, 1944. Rock-Ola also produced approximately sixty "presentation" carbines as gifts to company executives and other officials. Presentation carbines were finished in polished blue rather than the dull Parkerizing used on military weapons, and were accompanied by a custom-made wooden case including the name of the recipient engraved on a brass plate. Some of the presentation carbines had no serial numbers, while others were numbered in a special sequence preceded by "EX". Military production carbines had serial numbers in the following range: