Sounds like you got a good deal even though the maint issues, I'd keep the bull barrel if its still good, may not be ideal for you, but I'd say its a keeper. Just shoot .223. .223 is widely available so I wouldn't worry with the 5.56. Sounds like a good coyote setup or something along those lines.
Navin R. Johnson: "He hates these cans!!!! Stay away from the cans!!!!"