OKLAHOMA CITY — Angus McQueen, longtime CEO of the public relations firm that shaped the National Rifle Association's most memorable messages until an acrimonious split last month, has died.

Henry Martin, chief creative officer of Oklahoma City-based Ackerman McQueen, said Wednesday that Angus McQueen died on Tuesday following a battle with cancer. He was 74.

Ackerman McQueen was responsible for crafting the NRA's aggressive messaging for two decades. But the two severed ties last month amid turmoil within the powerful organization and accusations of financial misdeeds.

The NRA has filed several lawsuits against Ackerman McQueen, accusing it of refusing to document its billings and of seeking to undermine the association. Ackerman McQueen has filed countersuits, claiming that the NRA is trying to renege on its financial obligations and smear the public relations firm.