In the early 2000s, pros were still using one iron model through the bag, which meant the long irons were unforgiving blades in many cases. The philosophy began to change around 2010, as blended sets (using more than one model) surged in popularity. In most cases, that meant replacing a blade 3- or 4-iron with a slightly more forgiving cavity-back or hollow-body model. Today, more than 60 percent of tour pros have a blended set—and it's even more commonplace at the recreational level.

This brings us to Chris Gotterup, who was one of the few remaining holdouts still wielding a blade 4-iron (Bridgestone 220 MB) on tour. That recently changed at the BMW Championship when he inserted a prototype Bridgestone B-Forged 100CB 4-iron. The cavity-back model gives Gotterup a bit more heel-toe forgiveness, which is a nice-to-have on Sundays when the pressure cranks up. The B-Forged is already available for pre-order in Asia, so there's a chance Gotterup's newest addition will make its way to the States.