EC Comics lead the way with Two-Fisted Tales, a bi-monthly, comic published in the early 1950s. The title appeared on newsstands with the November / December 1950 issue. Frontline Combat, also an EC comic, first hit the stands in July / August, 1951.
DC Comics followed suit in 1952 with Our Army at War (August, 1952), Star-Spangled War Stories (August, 1952), All-American Men of War (August / September, 1952), Our Fighting Forces (October / November 1954) and G.I. Combat (January 1957).

Probably the most highly productive publisher of war comics was Charlton Comics, who's titles included Soldier & Marine Comics (Dec 1954), the Fightin' series --- Army (Jan, 1956), Navy (Jan, 1956), Marines (May, 1955), Air Force (Feb 1956), Battlefield Action (Nov, 1957), War At Sea (Nov 1957), and many other war related titles.

By 1984 most of the war themed comics were dead, although some were revived through Trade paperback comics (several issues of a comic series in one volume).
Here's the list of War Comics available on the website:
Fightin' Air Force, 1956 (Charlton): 017,026,028,048,049
Fightin' Army, 1956 (Charlton): 020,026,044,053,054,055,065,080,081
Fightin' Marines, 1955 (Charlton): 016,022,061,088,089,092,102,103,105,108
Fightin' Navy, (Charlton): 079,111,127,128
G.I. Combat (DC Comics): 001,050,052,062,064,065,067,069,070,071,074,076,079,082,092
Our Fighting Forces (DC Comics): 001,002,003,004,005,006,007,009,010,011,012,014,017,019,022,024,025,028
Sgt. Fury and his Howling Commandos (Marvel Comics): 001,002,003,004,005,006,007,008,009,010,011,012,013,014,015,016,017,018,019,020,021,022,023,024,025
Sgt Rock (DC Comics): 302,304,305,309,310,314,315,319,320,321,322,328,329,330,331,335,336,337,338,80 Page Giant 07
