Mizuno Pro 243 irons / Official R&D Summary

Director of R&D, David Llewellyn outlines the key updates to Mizuno’s ‘Tour Speed’ iron – the Mizuno Pro 243. More compact and precise than its predecessor, yet faster from the face and more satisfying at impact. Improvements in performance only made possible through the long-term relationship between Mizuno’s R&D team and its exclusive Grain Flow Forging plant in Hiroshima, Japan.

You know I could see this this model having a a a really nice place within the iron Universe in terms of that player who can appreciate head shape but is looking for some technology in the 4 through S Iron within the player distance category there’s there’s there’s almost two categories in inside that models that aren’t quite game improvement looking but they still are pretty large size head maybe a little bit less offset than traditional game improvement spec and then there’s really what we were going

After with the Muno pro 243 where you have the distance technology the losss are a little bit stronger but not super strong there there’s Co there lower and deeper center of gravity on the 4 through 7even iron to help with launch so we’ve definitely enhanced the distance but we didn’t let

The head get overly large and a matter of fact in this case going from the previous model to the Muno pro 243 we actually made the head more compact we made the Top Line a little bit thinner thinned out the sole a little bit by using the the wraparound grind so I I

Would say what we’re we’re trending towards within the Muno Pro family specifically the 243 is in terms of head size and shape let’s make it more players and then at the same time which is difficult s multaneously enhan the performance in terms of uh launch and ball speed and

Distance in order to achieve the performance enhancements that we were looking for it it was actually a challenge un under the current set of rules that we had for forging we were limited a little bit in how thin we could go on the face but our Engineers

Working with our partners at chuo kogo they figured out a way that they could go even thinner than the previous model about 0.2 mm thinner what that was able to do in combination with actually having a a wider micro slot wider micr slot more rebound area thinner face more

Rebound overall we’re able to increase the co of the head so we’re increasing ball speed this is actually the thinnest we’ve gone on the face in terms of full body forging and how we’re able to do it uh first of all is the the the material

That we chose is a chromal 4120 which is an extremely strong material but also our our Engineers every year are advancing their CAE analysis so they know the limitations of the material and they can simulate how thin they can go uh before it before it crosses over a

Threshold in terms of stress so even before we we even cut a mold we we can understand like what is the limit of this material and then we can work with our partners at choyo to figure out how to get it down to that thickness that we

Think is as far as we can go uh without having any uh stress issues another process within the um Precision forging stage for the chali models is what’s called Spray quenching so after the hydraulic mold uh hits it and squeezes it and moves back up then there’s

Actually a spray quench to uh cool down the face part very quickly and kind of lock in the grain structure and lock in that strength of the face and but we’re selectively cooling the face and not cooling the hosle so that the hosle uh keeps some level of malleability for

Bending while uh getting the strength requirement we need for the uh for the very thin face it’s almost like the the 4 through seven iron get all the Talking Points within the set but the 4 through 7 iron are the chrom AL material with the thinner face the co but you also have

This 8 through gap wedge that are really nice 1025 m carbon steel proper player shallow cavities um that that Merry up with the the the 4 through seven iron and making that really nice transition from the seven iron to the eight iron through how we do the micr slot

Technology basically uh the micr slot technology on the four and five iron are going to give you the thinnest face and the widest rebound area and then as you get to the six and seven iron that re uh face gets a little bit thicker and the rebound area gets a little bit smaller

As you transition to the 8 through gap wedge I’m excited about potential adoption of the Muno pro 243 at the tour level I think some of the enhancements that we made in this cycle very much trying to push it that way in terms of head shape and size Topline thinner Top

Line uh more compact profile at address did some work on the sole to uh improve the turf interaction throughout the set very consistent so um I I do think that this has a tour application definite definitely that’s that’s kind of the way we’re pushing it like we pushing to

Increase the performance but at the same time having very much a a player’s profile the dress