Redbeard, by Michael Resnick

Redbeard takes place in the post-apocalyptic American East Coast, and details the struggles between the mutants born from the atomic fallout, and the Normans (the normal people who survived). The titular character is a hotheaded, savage blowhard too stupid to realize that he's being played by both sides of the conflict, and just street-smart, battle-hardened and lucky enough to survive and somehow rise in the political and social ranks of the ruling lords.

It's not a great book by any stretch, but it is a fun read. It's brash and violent, like a mix between Conan and the Horse Clan books with Groo the Wanderer in the lead role. I wouldn't seek it out, but if you stumble across a copy you could spend your time with worse books.