The Powder Horn was the official regimental publication of a U.S. Army infantry regiment stationed in the Panama Canal Zone/APO 827 during World War II — essentially a “waiting war” morale magazine for the GIs of that regiment, covering regimental news, sports, promotions, humor, cartoons, and life in Panama (Carnival, jungle training, local beer, etc.) rather than combat reporting, since the regiment’s mission was defending the Canal rather than fighting overseas.
Masthead staff for this issue (Vol. 1, No. 9, March–April 1945):

T/5 Sidney J. Moss – Co-Editor
T/4 Robert Schmidt – Co-Editor
T/5 Gonzalo M. Ramirez – Art Editor
T/5 George W. Rich – Cartoonist/Illustrator
Pfc. George Keys – Staff Artist

It was authorized by the regimental commander, Col. Harry D. Scheibla, censored by Capt. Lester N. Bolyard (Regimental Intelligence Officer), and supervised by Capt. Irvin S. Maddy (Regimental Information and Education Officer), with lithography by the Department Engineer Reproduction Plant and mailing/reprint rights handled via Camp Newspaper Service in New Orleans.