Who says Angels can't be Hunters?

He could see out of his new double's eyes, and heard his brother's voice, "Amateur hocus pocus. Don't forget, you learned all your tricks from me, little brother," Then Lucifer plunged the blade into his chest. Gabriel gasped and expelled the vision, making his double die, staging his death once more, charred wings and all.

"I guess I learned a few more tricks away from home,"

OR:

Gabriel escapes death and joins Dean, Sam, and Cass in their attempt to stop the apocalypse. Who said angels can't be hunters?

((note: This is set in season 5. I know Gabriel doesn't really die in canon, and comes back season 9, but for fanfiction purposes, Gabriel doesn't die and makes his way back to the Winchesters.))