The demographic that would instantly think of a rather nasty beer when hearing COLT .45 probably would not be reading this, so we'll assume you know that Colt .45 (also known as The Colt Cousins) was an American Western series which aired on ABC between October 1957 and September 1960.
Dell produced nine issues of the comic (3 under the Four Color numbering). This story is from issue #4, February 1960 and was drawn by John Ushler.