3/10 second or less

[BktBallRef]

Correct.

About 12 years ago, I believe it was an MLK holiday game, the Knicks and Bulls were playing in MSG. Bulls were up 1 with 0:00.1 remaining, kicks ball for a throw-in. The Knicks inbound the ball to Trent Tucker who catches the ball, turns and puts up a 3 from the corner. The horn didn't sound until the shot was almost to the basket. The shot went in, the officials counted it, and the Knicks won.

Obviously, the clock operator failed to start the clock when he was supposed to. Within a few days, the NBA instituted a rule that stated only a tap could score with 0:00.3 or less on the clock. THe NCAA and the NF soon followed.

Here endeth the lesson.