July 27, 2011 Titleist 712 Series MB Irons Edit Delete Tags Autopost For 2012, Titleist adjusts the sole and the finish of its popular, better-player muscleback iron, but intentionally avoids making major changes. Source: http://www.golf.com/golf/equipment/article/0,28136,2080582,00.html?cid=feed-equipment-20110630-2080582golf schools british open golf 2010 rules of golf