Mizuno player's irons have been in my bag for the better part of the 2010s. I've gotten to know several sets well, including blades, player's cavity-back irons and the new MMC (multi-material construction) line.
So, my curiosity is always piqued when Mizuno introduces new player's irons. With some of the design and features behind the new MP-20 line of three iron sets, I couldn't help but gawk at pictures in my feed for minutes on end.
The design of the MP-20 irons are a bit of a throwback. As you'd expect, two of the MP-20 iron sets are Grain Flow forged from 1025E Pure Select mild carbon steel, with the grain of the steel compacted tighter in the hitting zone. What's unique is each iron also features a copper plating to improve feel, just as was found on the TN87 blade, beneath a nickel-chrome protective layer. There's chrome, on nickel, on copper, on nickel, on steel.
Curiously enough, Mizuno didn't seem convinced the copper plating would create a measurable difference in performance. And, well, they were right. But in testing with touring pros, the best in the world picked the copper-plated set not knowing it was underneath the outer coating. The quantitative explanation isn't yet there, but the qualitative one suffices for now.
There are three sets in the MP-20 line: the muscleback MP-20, the MP-20 HMB (Hot Metal Blade) and the MP-20 MMC, each designed for different players and their needs.
The MP-20 ($1,300 for a set) is a classic muscleback set. It's a classic Mizuno look with some modern finishes and details. The lines were made in a modern-clean aesthetic, with the sole boasting more camber for flexibility and better turf interaction. In each iron, the topline was tapered differently to help move center of gravity, from none in the long irons to increasing amounts down through the short irons.
The MMCs ($1,225 for a set) are the second generation of the concept, first introduced in the MP-18 line. The topline is thinner than the MP-18 MMCs and more defined scoring lines. There's a tungsten sole weight to drive down the center of gravity for some help in improving launch conditions, while a titanium muscle plate reduces the weight behind the face with the support of a stronger, lighter material. The volume of tungsten in the toe portion of the sole decreases by 1.5 grams from the long and mid-irons to the scoring clubs.
The HMBs ($1,400 for a set), somewhat derived from the JPX Hot Metal irons that have proven popular, are a set of hybrid, hollow-body irons with a tour-inspired look. Effective, the HMBs are a set of irons taking the concepts found in long-iron replacement utility irons down through the set. The HMBs body is forged from the carbon steel but the whole hosel and face are forged together from a single piece of 4135 Chromoly, which is an alloy of chromium and molybdenum. That was to make the face as thin as possible for explosive distance. The face is laser welded to the steel body to reduce unnecessary weight and keep the topline inline with what better players prefer.
In totality, the three iron sets can be sold separately, but they're just as well to be sold in mix-and-match combinations. Not everyone want hollow-body irons from long-iron through wedge, so there may be some of those mixed in with musclebacks. Maybe a player like me would want MMCs in the 4-6 irons, with an HMB in the 3- or 2-iron, but I'd need musclebacks with the scoring clubs.