Springfield (Ill.) Firefighters' Pension Fund rehired Banc One as sole manager of its $68 million in assets, said Ray Moser, recording secretary. Trustees began a shortlist search for other firms, all with offices in Springfield, because they felt it was their fiduciary duty, Mr. Moser said. Morgan Stanley, U.S. Bank and National City Bank were the other finalists. Banc One's new three-year contract is expected to start March 1, Mr. Moser said. No consultant was used.