How Mizuno’s ST230, JPX 923 & S23 clubs helped this 1 handicap

The author plays a shot with a Mizuno JPX 923 Tour 8-iron.

Jack Hirsh/GOLF

Welcome to GOLF.com’s ClubTest Proving Ground, where Managing Equipment Editor Jonathan Wall and Senior Equipment Editor Ryan Barath — along with a cast of GOLF writers and editors — put the latest designs and groundbreaking technology in the equipment space to the test on the range and the course. For 2023 ClubTest, we paired members of our staff with the latest gear from manufacturers to give you, the potential club buyer, “a real feel.”

TESTER: Jack Hirsh (Assistant Editor) | 1HCP

GOAL: Find more accuracy with the driver, consistency and playability with irons, and versatility with wedges.

THE LOW DOWN: While I never fulfilled my childhood dream of getting a college golf scholarship and making it onto the PGA Tour, I’d like to think I’m no slouch on the golf course. After all, I grew up around the game with a father who works in the golf industry, and in a family of three avid golfers.

Of course, working full time has put a dent in that and these days I’m around a 1 handicap, but the potential is surely there to return to the hallowed plus handicap grounds if I can just add a little bit of consistency back to my game. My clubhead speed isn’t crazy fast — around 111 to 112 mph, but I’m used to being in the longer half of a foursome. What comes with that speed is a little bit of wildness and a pretty high launch. It’s interesting to think about how when I was professionally fit for golf clubs for the first time in high school, I was put into a high launch driver shaft, but by the second time, while I was in college, I was in an extra stiff , low product launch and have been since.

With irons, I’ve only ever played forged clubs with fairly thin toplines. As soon as I grew out of my US Kids Golf clubs, my dad fashioned me a set of Ben Hogan Apex Pluses from the late 1990s and I’ve used a similar clubhead ever since. Thin toplines, and narrow soles, but a pretty full cavity in the club. I’ve definitely benefited from new technology and material usage in my previous set of irons that have allowed for those small profile characteristics with more perimeter weighting.

Wedges are most important to me as you can tell from my description above, I didn’t hit it very far until college, and because of that, I don’t hit it all that straight. But I can get up and down from anywhere. My creativity around the greens has always been my strength. That’s been despite my reluctance to use any other wedge makeup than a 52˚ and a 58˚. I thought I could hit any shot I wanted with that setup.

With all that said, I’ve also grown up as a wannabe gearhead. My dad has always had an amateur club-making setup in our basement or garage where we do our own gripping, re-shafting, etc. I don’t dive too deeply into loft/lies, but when I’ve been in places that had one, I know how to check and adjust my loft and lies as needed.

My fitted gear:

The author plays a shot with a Mizuno ST 230 Z driver.

Jack Hirsh/GOLF

DRIVERS: I was fit for Mizuno’s new ST-Z 230 driver. This is the lower spinning of their two models, sits a little open at address (a common preference for a better player) and features a slightly more pear-shaped head and lacks the draw bias of the ST-X. Both drivers feature Mizuno’s Quick Switch Hosel Mechanism, which allows for 4˚ of loft adjustability. I had a 9.5 degree head, which I lofted down to 8.375˚, similar to my gamer which was a 9˚ head I played at either 9˚ or 8.25˚.

The crown jewel of the line is the new CORTECH Chamber which Mizuno says is the “missing piece” to help elevate its woods from the shadows of its irons. The chamber is a molded stainless steel weight, encased in TPU material (that stuff you don’t know if it’s rubber or plastic) positioned on the sole, just behind the face. Mizuno said it allows the sole greater flex, leading to increased ball speed, along with sound, and feel improvements.

What I found, is despite being the “better players” head, the new ST-Z was incredibly forgiving. My average top ball speeds across testing between the ST-Z and my gamer driver (which was a 2022 model that I loved), but the average ball speeds were more than 1 mph faster with the ST-Z (164.2 vs. 163.0). Not only more forgiving ball speed numbers, but more forgiving dispersion as well (as you can see from the shot chart below). I was hitting my tight draw easier.

The author’s dispersion with the Mizuno ST-Z 230 (red) and gamer driver (blue).

Jack Hirsh

The driver’s forgiveness was also proven on the course when a horrific swing somehow found the middle of the fairway (I have witnesses). Check out the impact location below.

Believe it or not, that ball, hit way out on the toe, found the center of the fairway.

Jack Hirsh/GOLF

FAIRWAY WOODS: I’m one of those guys who carries a slightly older model 3-wood that makes a fitter shiver in their boots when they see it. It may not be Tiger Woods’ 8-iron from 2000, but my 3-wood is the closest I’ve ever come to “dime’ing out” the sweet spot of a club. I want to have a strong lofted (13-14˚) 3-wood I can mash off the tee and reach the longest par-5 greens in two. My next club down, be it another fairway wood or a 2/3 hybrid, is something more versatile to play out of the rough or stop quicker on firm greens.

The matching ST-Z 230 3 and 5 woods accomplished both of these needs for me. The clubs again feature the new CORTECH Chamber from the driver and some additional weight in the back of the head to promote a higher launch. The ST-Z (there is no ST-X option this year) does not come in stronger than 15˚, but with the 4˚+ of loft adjustability, that was no issue, as I was able to loft down one setting to 13.375 ˚ and get the second driver I like (with ball speeds that broke 160 mph!). It also had just a touch more spin, which gave me a nice boost of control and versatility.

The 5-wood I was a bit skeptical of playing with a fairly large head (177 cc) compared to my gamer 5-wood (140cc). However, the improved weighting of the head and launch characteristics allowed me to dig balls out of any lie I could with a smaller club and the flight hits the exact window and carry I want it to. Plus with the adjustability to make the 18˚ 5-wood as strong as a 4-wood or as weak as a 7-wood, this club can be whatever the course calls for it to be.

Driving iron: I was fit for a Pro Fli-Hi 3 iron to alternate with my 5-wood. This club is a bit meatier than my previous driving iron, but the black finish helps disguise the size and I’m actually able to get a little more ball speed thanks to the MAS1C steel face, which is the same material used in Mizuno’s fairway woods .

Mizuno’s JPX923 Forged and Tour irons.

Mizuno golf

Mid/long irons: For full transparency, I was pretty giddy to draw Mizuno for clubtest. My only two sets of adult irons have been Mizuno irons and my parent’s basement is a treasure trove of classics including MP-30s, MP-60s, MP-52s, JPX-800 Pros and more. For the rest of my irons, I went with a split set of the new JPX 923 line. This year’s line features five models, which actually fit in very nicely with last year’s three Mizuno Pro models. The three more game improvement models (JPX 923 Hot Metal Pro, Hot Metal and Hot Metal HL) were released in the fall while the JPX 923 Forged and Tour are being released at the start of the year to give each line a time to shine.

For my 4 through 7-iron, I tried out the JPX 923 Forged. This iron can fit in right between Mizuno’s 225 and 223 irons as a forged cavity back that provides the fast ball speeds of a hollow-bodied model (the 225), but fits in a smaller profile like a muscle cavity (the 223).

The new V-Chassis helped Mizuno allow the topline of this iron to be thinner than ever, while still retaining that classic Mizuno forged feel. The Forged also poses a microslot behind the face in the 4 through 7-irons that help juice ball speed numbers. This is tech borrowed from the Hot Metal family. I’m finally able to look at an iron that gives more forgiveness and ball speed while maintaining the compact look I like.

With these irons, I noticed about 1-2 mph of ball speed gains, while also seeing slightly higher spin and peak height numbers. This ended up meaning these irons flew a few yards farther than my old ones while stopping quicker. The total distances were similar, but if I can get more of that number through the air, rather than roll, while maintaining the ability to fly it down, I’ll take it.

Short irons: From 8-iron through PW, I have the new JPX 923 Tour. These are like daggers. Mizuno has created a cavity back iron with muscle back like feel thanks to its “Harmonic Impact Technology.” You’d be forgiven for thinking you were hitting a conventional blade when swinging the 923 Tour before you realized the sweet spot is actually a reasonable size. As a pure player’s iron, these clubs allow me to work the ball in any direction I like and the slight cavity gives me some wiggle room with mishits. The microslot technology in the Forged and other JPX models isn’t present in this one, but that tech isn’t in the scoring irons of the JPFX 923 Forged either, making the 7-8-iron transition the logical place to break a set .

I shouldn’t need to break up the classic Mizuno feel here, but it might be better than ever with a copper underlay, a first for JPX iron. These irons allow you to have pinpoint precision with your shotmaking, but allow just enough wiggle room with mixits to be playable.

The author plays a shot with a Mizuno S23 sand wedge.

Jack Hirsh/GOLF

WEDGES: The new S23 wedges were perhaps my biggest surprise. I’ve never been one to venture off from traditional shapes. So when I saw a cavity back wedge resembling the 2015 Nike Engage, I thought these would be more targeted to the mid-to-high handicapper than myself. I was very wrong.

The cavity has allowed Mizuno to move the center of gravity toward the toe, which is where most shots around the green are struck from. Not to mention these wedges use the same forging as Mizuno’s irons, making the feel super consistent with the irons.

The S23s are designed to flow seamlessly from the JPX 923 Forged irons I have in the top end of my set, but I don’t see any reason they don’t work well coming from the JPX 923 Tours I have.

In a first for me, I switched up my normal 52˚, 58˚ gapping (with a 62˚ thrown in there as of late) for a 50˚, 55˚, 60˚ setup to help even my full swing gapings given the 62 It wasn’t very useful outside of 30 yards.

Results

While I didn’t make significant distance gains, I still had huge performance gains in dispersion and consistency. This was not my first time being professionally fit, so seeing improvements over my previous set was going to be challenging, but it’s safe to say the mission was accomplished.

With the ST-230 line and JPX 923 line, Mizuno has proven two things: 1. the JPX line has as much to offer better players as it does beginners. 2. Mizuno’s drivers can come out from behind the shadow of its more famous iron offerings. I now have a driver I’m as confident in finding the fairway as I am attacking flags with the irons.

Mizuno irons are once again a great option for anyone looking to upgrade, but this year so is the driver.

Want to overhaul your bag for 2023? Find a fitting location near you at GOLF’s affiliate company True Spec Golf.

Jack Hirsh

Golf.com Editor

Jack Hirsh is an assistant editor at GOLF. A Pennsylvania native, Jack is 2020 graduate of Penn State University, earning degrees in broadcast journalism and political science. He was captain of his high school golf team and still *tries* to remain competitive in local amateurs. Before joining GOLF, Jack spent two years working at a TV station in Bend, Oregon, primarily as Multimedia Journalist/reporter, but also producing, anchoring and even presenting the weather. He can be reached at jack.hirsh@golf.com.

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