Iron Byron was the USGA’s original mechanical golfer used for testing golf clubs and balls. The device was purchased in 1972 and was officially retired in 2004 when it was replaced by a servo-electric, mechanical golfer manufactured by Golf Laboratories. The memorable and catchy nickname came from the fact that the machine was modeled after Byron Nelson’s golf swing. For over 30 years, Iron Byron hit 400 to 500 golf balls a day in the Spring and Fall at a consistent swing speed of 109 miles per hour, which represented the top tier of swing speeds at the time. The new mechanical golfer swings at 120 mph, which is more in line with the top swing speeds of today. Iron Byron was fundamental in the development of the Overall Distance Standard for golf balls, which was first added to the Rules of Golf in 1976.