This is Giant Western Comics 1, published by Mimosa (SA Magazine Co) in 1962.
It reprints the cover and both stories from DC Comics' All-Star Western 117 (1961):
Johnny Thunder: "Six-Gun Showdown with Madame .44"
Super-Chief: "The Crowning of Super-Chief"
Also reprinted are these three stories from DC Comics' All-Star Western 98 (1957):
Trigger Twins: "The Cavern of Doom"
Johnny Thunder: "Outlaw Target"
Foley of the Fighting Fifth: |"The Strange Battle at Comanche Creek"
48pages, glossy colour cover, black and white newsprint interior.
Here is the cover of issue 1 and DC Comics' original cover:
Mimosa Western Comics Series