PRESIDENT BUSH said this week he is open to a ``sensible answer'' to the proliferation of semiautomatic assault weapons and has asked William Bennett, his nominee for drug policy coordinator, to work on it. Mr. Bush, a member of the National Rifle Association, has said he opposes a ban on such guns. In a news conference this week, he said he talked to Mr. Bennett about the problem after Bennett was quoted as saying he might favor curtailment of such weapons as a way to cut down on drug-related violence. Bush said he told Bennett: ``I'm not so rigid that if you come to me with a sensible answer that takes care of the concerns that I've felt over the years, I'll take a hard look at it, and I'll work with you to that end.'' He said he wants to find ``what can be worked out with finality on AK47s ... and still do what's right by the legitimate sportsman.''