Hawaii Five-O (1968) - Season 5Hawaii Five-O (1968) - Season 5 - Internet Movie Firearms Database - Guns in Movies, TV and Video GamesHawaii Five-O (1968) - Season 5
The Walther P38 is used by various characters throughout the series.
Nambu Type 14
A Nambu Type 14 pistol is used by a 'Bushido' during an attempt on the life of Leonard Tokura (Ricardo Montalban) in Season 1's "Samurai" (S1E04). Chin Ho identifies the pistol as a "Nambu, eight millimeter".
Submachine Guns
M1 Carbine
Different variants of the M1 Carbine are seen used in the series. In Season 2's "Savage Sunday" (S2E05), revolutionaries are armed with the M1 Carbine when raiding a military armory. In "Sweet Terror" (S2E07), McGarrett (Jack Lord) takes an M1 Carbine off a gunman. An M1 Carbine fitted with a scope, wire stock and forward pistol grip is notably used by an double amputee sniper in Season 6's "Hookman".
Madsen 50
The captain of the boat is seen with a Madsen M50 in the pilot episode.
A USAF honor guard performs a rifle volley with M1 Garands in the pilot episode.
M14 Rifle
In Season 2's "Savage Sunday", revolutionaries raid an armory that contains M14 rifles among other weapons. Since this episode was produced in the late 1960's, it's possible that these rifles are mocked up M1 Garands.
Other
M60
In Season 2's "Savage Sunday", revolutionaries raid an armory that contains M60 machine guns among other weapons. Since this episode was produced in the late 1960's, this was one of the earliest appearances of the machine gun seen in a television series.