Cooper was a little well a lot, overboard about the .45 auto. The fact that it was and still is a great gun helped.
He clearly was smart tho. He had one of the best comebacks I have ever seen when a CBS reporter asked him if violence doesn’t beget violence? Cooper’s reply was “I sure hope so”.
I do think he was capable of learning even if not admitting he was wrong. When I first started reading him, I think in the 60’s he used to say a hit with a .45 auto would stop a person 98% of the time. I later saw him call it 95%, then in his later years, I never saw him claim that again.
And yet, when Cooper lent his endorsement and expertise to what he hoped would be the ultimate sidearm (the Bren Ten), he based the design on an upgraded CZ75.