Robert Ryan was a tuff guy in real life was known as a good boxer.
Tex Cobb made the best of his ligit "tuff guy" image and was actually a very actor, limited in type but he did well.
For me the best was Charles Bronson don't know if he fought or not but just watch an obscure movie called "Hard Times" with Bronson and Colburn in the leads about a street fighter in the Depression era. That guy had some beautifull combos and his stance and balance was spot on. Definetly could have been in the ring!! Ray.