I just watched William Wiard's "Tom Horn" for the first time since it came out in 1980. Written by Tom McGuane and Bud Shrake and starring Steve McQueen in his next-to-last role, it's a lot better than I remembered. McQueen plays Horn as both childish, trusting naïf and casual killer, a man who never really understands the forces allied against him. It's beautifully shot by John Alonzo, with appearances from Elishah Cook, Jr, and Slim Pickens, it's one of the last of the great westerns of the period.
There's an interesting comparison to be made with Michael Cimino's "Heaven's Gate," another elegiac treatment of Wyoming's range wars. (If you've been avoiding "Heaven's Gate" all these years because of the critical drubbing it took over the issue of Cimino's profligate spending, do yourself a favor and check it out--it's a textbook example of contemporary critical consensus getting it dead fucking wrong.)