[BasketBallonlyfan]

"NO LESS THAN :00.3 must expire on the game clock when a player secures possession of an inbounds pass and then attempts a field goal. If less than :00.3 expires in such a situation, the timer will be instructed to deduct AT LEAST :00.3 from the game clock. If less than :00.3 remain on the game clock when this situation occurs, the period is over, and the field goal attempt will be disallowed immediately whether successful or unsuccessful."

That might be the NBA rules, but high school rules goes by the horn, not how many tenths of seconds are on the clock