Taking a Practice swing using a club with a weighted headcover or "doughnut".
Q.During a round, may a player make a stroke or a practice swing using a club with a weighted headcover or "doughnut" on it, or use any other device designed as a training or swing aid?
A.No. The player would be using an artificial device to assist him in his play in breach of Rule 14-3.
7-1. Practice Before or Between Roundsb. Stroke Play
Before a round or play-off on any day of a stroke-play competition, a competitor must not practice on the competition course or test the surface of any putting green on the course by rolling a ball or roughening or scraping the surface.
When two or more rounds of a stroke-play competition are to be played over consecutive days, a competitor must not practice between those rounds on any competition course remaining to be played, or test the surface of any putting green on such course by rolling a ball or roughening or scraping the surface.
Exception: Practice putting or chipping on or near the first teeing ground or any practice area before starting a round or play-off is permitted.PENALTY FOR BREACH OF RULE 7-1b:
7-2. Practice During Round
A player must not make a practice stroke during play of a hole.
Between the play of two holes a player must not make a practice stroke, except that he may practice putting or chipping on or near:
a. the putting green of the hole last played,
b. any practice putting green, or
Exception: When play has been suspended by the Committee, a player may, prior to resumption of play, practice (a) as provided in this Rule, (b) anywhere other than on the competition course and (c) as otherwise permitted by the Committee.
PENALTY FOR BREACH OF RULE 7-2:
Match play - Loss of hole; Stroke play - Two strokes.
In the event of a breach between the play of two holes, the penalty applies to the next hole.
(a) practice on or near the putting green of the hole last played, and
(b) rolling a ball on the putting green of the hole last played.