I tried Mizuno’s new irons against last year’s. Here’s what I learned

Welcome to I Tried It, a GOLF.com series about golf items — apparel, gear, accessories, etc. — that we’ve recently taken out for a spin. We’re here to give our honest, no-frills takes on the latest and greatest golf or golf-adjacent items. So, scroll down to read about what we love about golf’s newest (or new to us) products.

***

Have you ever seen a new golf club that looks so good that you’ll do whatever you can and ignore better judgment just to put it in your bag?

Yeah, that’s how we get to an article like this.

I’ve been a Mizuno irons player since my dad cut down a set of MP-52s and put some lead tape in the cavity to swing weight them properly — or at least better. Since then, I’ve had a set of MP-64s, which are regrettably not currently in my possession, a set of MP-18 MMCs, a combo set of the JPX 923 Forged and Tour, and then last year, I played a combo of Mizuno Pro 245, 243 and 241 irons.

Given my role as an equipment writer, I’ve hit a bunch of different OEMs’ irons. I’m sure one year, I will use another OEM’s set in competition, but for right now I’m still gravitating to what I know.

This year, when the company announced its new Mizuno Pro S-3 irons, I knew these were clubs I had to add to my bag.

The S-3 irons are the first in a new Mizuno Signature series within the fabled Mizuno Pro line of irons, as Mizuno’s Chris Voshall told me at the time of their release. They are a single-piece forged iron from 1025E Pure Select Mild Carbon Steel with the company’s Grain Flow Forging process for an incredibly smooth feel. They were also one of the first to feature a new Triple Cut Sole, which adds bounce to the leading edge to help with turf interaction.

Then I saw Mizuno staffer Ben Griffin at the WM Phoenix Open say that the S-3s were the best irons the company had ever made, strong praise for a company that has a storied history of forged irons.

But when a PGA Tour player (and eventual winner) tells you how much he loves a set of irons with cavities shallower than a kiddie pool and you’re a 2-handicap who hits 4 greens in a round every so often, that’s probably a sign that you shouldn’t be playing the same clubs.

Mizuno Pro S-3 Custom Irons

The Mizuno Pro S-3 irons epitomize refined craftsmanship and elite performance, combining Mizuno’s renowned forging expertise with the precision and versatility demanded by today’s golfers. With a sleek, compact profile and an exceptional feel, the Pro S-3 is the ultimate choice for players seeking precision and control in every shot.
Iconic Mizuno Pro FeelThe Mizuno Pro S-3 delivers the signature feel that has solidified Mizuno’s reputation. This exceptional sensation stems from the advanced Grain Flow Forged HD process, performed exclusively at Mizuno’s Hiroshima plant, and is enhanced by premium materials:

1025E Pure Select Mild Carbon Steel: Provides a soft, responsive touch that golfers love.

Copper Underlay: Subtly enhances vibration patterns, ensuring a smoother, more connected feel with every strike.

View Product

ALSO AVAILABLE AT: PGA Tour Superstore, Mizuno

Nevertheless, knowing the S-3s, with weaker lofts than the 243s that comprised most of my set, would give me some additional height that I was looking for, I replaced my short and mid-irons 6i-9i with the S-3. I still kept the 243 in the 5-iron and 245 in the 4-iron as the S-3 5-iron was just too difficult for me to get consistent ball speed out of.

This was in late February, so my swing wasn’t sharp or in mid-season form. So I wrongly discarded any mishits as just being out of practice and didn’t think much of it.

There was one shot in a match where I hit the 6-iron and hit the ball on the toe so badly that the ball ended up 30 yards short and right of the pin.

After two months and several competitive rounds, it was time for a reality check.

Pro 243 vs. Pro S-3

What are the differences between these two irons anyway? Both are Mizuno irons, both are forged with the company’s Grain Flow Forging Process, both have a similar offset and blade lengths, and both are designed to feel very soft and smooth at impact thanks a copper underlay. But that’s kind of where the similarities end.

The Pro 243s are what I like to call a speed cavity, which is somewhere in the middle of a players cavity-back iron and a player’s distance iron. Starting with the 7-iron, the 243s feature a microslot and two-piece construction to make the face faster. Those irons are also forged from 4120 Chromoly, which is faster than 1025 carbon. Compared to the S-3, the topline is actually slightly thinner to give the impression of a more compact iron, while the sole is slightly wider to make it more forgiving.

The 243s also have stronger lofts, which is part of the reason I wanted to switch them out, as I felt I needed more peak height and the S-3s were about 2 degrees weaker.

With the Pro S-3, a lot of that technology is left out for players who want precise scoring instruments. This is for the player who will feel even the slightest mishit and wants to fly their 7-iron exactly 175, not 177 and not 173. They can tell that subtle of a mishit. Voshall told me the Signature Line was started because feedback from the Tour staff was that they didn’t need new irons every two years, because the technology in a Tour iron doesn’t change that often. Therefore, the Signature line will have a four-year product cycle.

All the good shots I would hit with the S-3s were just as good as the ones I would hit with the 243s. On the course, I never noticed that I would hit a shot solid and not have it go as far as I needed it to.

The bad ones, that’s another story.

Testing

I went head-to-head with both 7-irons in the set inside using a Trackman

Both clubs were a .25″ long of Mizuno’s standard (37.5″ 7-iron), with Project X 6.5 shafts, swing weights were D5, lie angles were 1˚ to 1.5˚ degrees flat (60.5˚ 7-iron, the S-3s are .5˚ more upright standard) and the lofts were both 34 degrees (standard for the S-3, 2˚ weak for the 243). This test was also done with Titleist Pro V1 golf balls, which is the ball I play since I hit the ball pretty high and don’t need a ton of spin.

I took five swings with each club and as it just so happened, I mishit one of each.

At first glance, it actually appears that I generate higher ball speeds and spin with the S-3, although it goes shorter, and the dispersion, while centered better, isn’t quite as tight as with the 243. I like to draw the ball, so seeing that I had an easier time turning over the 243 isn’t a bad thing either.

You can also see that the mishit with the 243, while it was 3 mph slower than the S-3’s mishit, still flew four yards farther. That could be the difference between covering a bunker or getting plugged in a lip.

However, the data really gets clear when we remove those mishits with each club and focus on the averages with just my good swings.

Now we see the dispersion tighten pretty dramatically with the 243, while the S-3 is still pretty wide. Additionally, the consistency of my ball speeds and carry numbers drops down to almost negligible numbers.

On average, the ball flies almost three yards farther and stops just a half-yard longer. Since I hit the ball so high, I don’t really need a ton of spin, so 6500 is a great number for me. Another reason why the Pro V1 works so well for me.

This test isn’t about finding irons that go the farthest. If I wanted that, I would play a set of players distance irons. I want to know that when I make a swing with a 7-iron, it’s going to go the distance I expect it to.

The other really interesting insight here is that I was swinging the S-3s nearly a mile an hour faster than the 243. There probably isn’t much of an aerodynamic difference between the two clubs, so I assume that I was subconsciously trying to swing the S-3s faster in order to hit them as far as the 243.

That’s not a recipe for good, consistent golf!

Bottom line

The Pro S-3 is still an amazing iron. It’s got that same Mizuno feel to it that keeps its followers so loyal to the brand, they look beautiful at address and in the hands of the right player, are going to produce very consistent and precise results.

Unfortunately for me, I am not that player and it took me a bit longer than it should have, but I’ve accepted it.

Mizuno Pro 243 Custom Irons

The Mizuno Pro Irons are the result of a longstanding connection between Mizuno’s club engineers and the legendary Grain Flow Forging plant in Hiroshima, Japan. Every fraction of a millimeter and subtle curve has been meticulously considered, shaping the future of golf club technology.
Key Features of the Mizuno Pro 243 / Tour Speed:

Grain Flow Forged HD in Hiroshima, Japan

4120 Chromoly with Flow Microslot (4-7 iron)

Soft Copper Underlay for sensational feel

Harmonic Impact Technology for a soft muscle-back feel

Wrap Around Sole Grind for improved turf interaction

Exceptionally compact players’ profile

Increased bounce angle for enhanced performance

Full Satin Brush finish

Available 4-GW / RH only

View Product

ALSO AVAILABLE AT: PGA Tour Superstore, Mizuno

The first round I put the 243s back in the bag, ball striking just became so much easier. The ball was going where I was looking and I didn’t have to feel like I was forcing anything.

You’ll hear Johnny Wunder talk about “raising your floor” here a lot and while I could hit the S-3s great, they don’t “raise my floor” by mitigating my mishits the same way the 243s do. This game isn’t as much about making your best shots great as it is about making your worst shots better.

Both are fantastic irons, but for me and my game, I’m going to stick with the 243s because they are going to help me shoot the lowest score possible.

Want to find the best irons for your game? Find a club-fitting location near you at True Spec Golf.

“>