Many thanks to the responders above & especially to "Wyatt Burp" for the answer & providing the video. This matter is an example of the odd way in which a person's mind can work. I remembered the gun rig & Cameron Mitchell, an d the dialogue in the saloon: "Looks fast/is fast." I could not recall the title of the movie, the plot, or the names of other actors. Rory Calhoun was one of the better western actors imo.
"Vera Cruz" has been shown on one of the cable channels but had nothing special in the way of guns & rigs. Burt Lancaster & Gary Cooper were good in that movie, though Burt shooting behind his back I thought was a rather "far out" stunt. .
But I never ran across "Powder River" again until the above post. My apologies to you all for mot thanking you all sooner, but I've been busy with getting a new water heater & auto repairs over the past several weeks & had not taken the time to check on the forum.