Several sources have stated that Rick Jason was to carry the M1928A1 Thompson submachine gun. After two days of filming, Jason complained about the weight of the Thompson and switched to the lighter M1 carbine and carried it throughout the rest of the series. The M1 Carbine was designed primarily to be issued to officers, noncombat and line-of-communications troops. Vic Morrow was then given the Thompson to carry. After two weeks he also complained of its weight. A lighter replica Thompson was made out of wood and was carried by Morrow until it was time for a firefight, at which time he would switch back to the real Thompson. The replica can be seen with its incorrect ejection port.
Vic Morrow and Rick Jason were essentially co-stars, and for this reason there were two sets of opening credits, some listing Morrow as the lead before Jason, and some listing Jason ahead of Morrow, although not necessarily based on which one had a larger role in a given episode.
Although Pierre Jalbert had been employed at MGM for nearly a decade, he had no actual acting experience prior to being cast as Pfc. Paul "Caje" Lemay on the series. Up to that time his job at MGM had been in the capacity of a technician in the film editing department.
Comedian Charlie Callas was a big fan of the series and asked Rick Jason if he could have the M1 carbine Jason's "Lt. Hanley" character carried on the show after it ended. Jason had the gun's barrel plugged and gave it to Callas, who mounted it over the bar in his house. Since Callas' passing, the whereabouts of the weapon are unknown.
Originally aired on Tuesday nights at 7:30 p.m. opposite NBC's Laramie (1959), CBS' Gunsmoke (1955), and The Lloyd Bridges Show (1962).