Mizuno JPX923 Hot Metal, Hot Metal Pro and Hot Metal HL Irons Review

After fitting 350,000 golfers into a family of seven different golf irons, Mizuno felt they didn’t quite have enough different models to be able to offer the best golf irons for every single type of golfer. It’s a problem the company’s engineers and fitters have solved with the five-iron JPX923 family, which sits alongside the Mizuno Pro range.

Though Mizuno irons have grown in popularity on tour recently thanks to fewer equipment contracts, the brand’s fitters have spotted club golfers are trending toward more moderate swing speeds. And as we’ve said many times before, slower swing speeds aren’t well suited to flighting shots for maximum distance and stopping power, particularly at modern strong lofts.   

“We’re constantly evolving the JPX series using the unique swings we capture every year on the Mizuno shaft Optimizer” says Bill Price, Director of Fitting at Mizuno. “We’re seeing an increase in the number of players with slightly slower swing speeds being fitted – and a trend to more shaft lean”.

To counteract the trend the company have increased bounce on all five JPX923 models and introduced a new, more lofted JPX923 Hot Metal HL (high launch), to specifically benefit lower speed players.

Just like their predecessors (JPX919 and JPX921) the five JPX923s are designed to help all golfers get more from their game. Whether you’re an elite tour pro or slow swinging amateur – or anywhere in between – there’s a JPX923, and one of 50 custom shaft options, to suit you. With the JPX923 Hot Metal models already in store and the Tour and Forged arriving in February 2023, here’s our guide to deciding which will benefit your own game.

Mizuno JPX923 Hot Metal Pro iron

RRP: £150 per club | VIEW UK OFFER | VIEW US OFFER
Stock shafts: Choose from 21 premium options | 7-iron loft: 28.5° | Forgiveness rating: 3/5

All three JPX923 Hot Metal models are made from Mizuno’s new cast nickel chromoly material, which is 35% stronger than the original Hot Metal. Mizuno say the 4335 nickel chromoly, which is both springy and strong, lets their engineers reduce face thickness by 8%.

It means the thinnest, highest energy part of the face can be extended by 18%, which delivers additional consistency to shots hit off centre. Thanks to using a cup face construction, golfers can expect high launch, with controllable landing angles and good stopping power, even though lofts are slightly stronger than previous models.

Mizuno say:

The Hot Metal Pro is a players’ speed cavity that’s compact, with minimal offset. It’s for consistent ball-strikers seeking maximum ball speed. Typically the model falls into the hands of low to mid-handicap golfers.

Verdict: Mizuno JPX923 Hot Metal Pro iron

The whole reason the JPX Pro iron originally came about was thanks to Mizuno’s Chris Voshall (Product Lead) spotting how some seriously good golfers choose Hot Metal irons because they were fast and long, but ideally they’d want that performance in a slightly smaller chassis. The Pro fills that gap between a Players’ iron and Mid-Handicap model beautifully, ranking as one of the best players’ distance irons around.

If you’re thinking the Pro could be your next perfect set of irons we’d seriously advise holding off until the matching JPX923 Forged is launched early in 2023. Our thinking is for reasonably consistent ball strikers there’s real decisions to make between the JPX923 Pro, JPX923 Forged and hollow body Mizuno Pro 225.

Our test data highlights (thanks to the 1.5° stronger 7-iron loft) how the Hot Metal Pro is a very strong performer against the Pro 225, with 1.7mph faster ball speed and 4 yards more carry distance. Thanks to slightly lower levels of offset and sole width our numbers also show how those specs lower launch and shot height whilst also shallowing descent angle a fraction too, so be warned this is a set of reasonable speed players.

In the right hands this cracking model will rival any of the best player’s distance irons on the market in 2023.     

How the three Mizuno JPX923 Hot Metal irons differ

Mizuno JPX923 Hot Metal & Hot Metal HL iron

RRP: £135 per club | VIEW UK OFFER | VIEW US OFFER
Stock shaft: Choose from 21 premium options | 7-iron loft: 28.5°/ 31° | Forgiveness rating: 3.5 – 4/5

RRP: £135 per club

7-iron loft: 28.5°/ 31°

Category/Forgiveness rating: Mid-high handicap 3.5 / Moderate speed players 3.5

By analysing the swings of 350,000 golfers Mizuno realised there’s a trend towards slower speeds. The research led them to develop a higher lofted JPX923 Hot Metal Pro HL (High Launch) model which targets moderate speed players and those with aggressive shaft lean.

The JPX Hot Metal family has targeted mid–high handicap players for a while now, expect a larger profile with additional hosel offset and wider soles. All three models are cast, not forged like the JPX923 Tour and Forged, which explains the lower cost. For this generation the 7-iron lofts are 0.5° stronger than previous models, with the HL being 2.5° weaker (in the 7-iron) to help maximise spin, stopping power and carry distance at moderate speed.

Mizuno say:

The JPX923 Hot Metal is a forgiving speed cavity for mid to high-handicap players, the HL is a high launch version for slower speed players. 

RELATED: Everything you need to know about the Mizuno JPX923 Tour iron

Verdict: Mizuno JPX923 Hot Metal iron

We’ve been criticised here at TG before for saying the two previous generations of Mizuno JPX Hot Metal irons best suited golfers up to about a 24 handicap. Our thinking is there’s slightly more forgiving irons out there, which is an issue Mizuno have absolutely addressed with the new HL, which begs the question where does the standard model now sit?

See the standard JPX923 Hot Metal as Mizuno’s most forgiving, distance focused iron for reasonable swing speed players and you really won’t go too far wrong. As far as the best mid-high handicap irons go, you won’t find a nicer more attractively shaped iron in the category. This model has none of the ugly hallmarks of traditional big body game improver irons.

Our test data shows this model is more than a match for the very best mid-handicap/game improver irons available, so long as you have reasonable levels of speed to launch the strong lofts to a decent peak height with reasonable spin and descent angle.

With 21 shaft options to choose from (in the UK) make sure you get fitted. If your 7-iron swing speed is close to 75mph look at the lighter, higher launch Nippon N.S. Pro 950GH and 950GH Neo shafts for optimal performance.   

WATCH: Best 2023 Mid-Handicap Iron video

Who is the Mizuno JPX923 Hot Metal HL iron for?

Of the 350,000 fitting sessions Mizuno have conducted using their shaft optimizer, 27% of golfers measured have recorded a 75 mph or slower when swinging a 7-iron. That’s 1 in 4 golfers. Mizuno say at roughly 73mph (club speed) the carry distance between the new JPX923 Hot Metal and Hot Metal HL becomes negligible, so the new HL model is likely to best suit golfers swinging a 7-iron at 75mph and below.        

How do the three Mizuno JPX923 Hot Metal irons compare in data?

Verdict: Mizuno JPX923 Hot Metal HL iron

By putting a number on what constitutes ‘moderate speed’ Mizuno have done players a massive favour in upping understanding of where their iron game sits and which models suit them best. We love how Mizuno’s design brief included avoiding a super game improver iron look, whilst providing SGI levels of performance in the HL. What they’ve produced absolutely nails their goal as the head gives no impression of being a super game improver model.

At our test pro’s higher speed our data shows the HL is 10 yards back from the standard Hot Metal model in terms of carry distance, but at the speed it’s designed for (75 mph and below) this simply won’t be the case. If the model truly suits you it will generate just about longest carry distance when compared to the standard Hot Metal model, it will also flight shots higher, with more spin and have a steeper descent angle, so you’ll score more efficiently. 

We feel the Mizuno JPX923 Hot Metal HL is one of the best irons for high handicaps.

If you’re swing speed is anywhere close to 75mph (with a 7-iron) be very wary about teaming this model with anything other than the lighter, higher launching iron shafts from Mizuno’s fitting matrix. Anything else is just counter intuitive to their design, unless of course you’re a high speed player with aggressive forward shaft lean playing the HL for more dynamic loft. 

WATCH: Best 2023 Moderate Speed/High Handicap Iron video

Loft Comparison: Mizuno JPX923 iron family

READ NEXT: Which Mizuno iron is best for me?

Mizuno JPX923 Hot Metal Pro iron

RRP: £150 per club | VIEW UK OFFER | VIEW US OFFER
Stock shafts: Choose from 21 premium options | 7-iron loft: 28.5° | Forgiveness rating: 3/5

Mizuno JPX923 Hot Metal and Hot Metal HL iron

RRP: £135 per club | VIEW UK OFFER | VIEW US OFFER
Stock shaft: Choose from 21 premium options | 7-iron loft: 28.5°/ 31° | Forgiveness rating: 3.5 – 4/5

RRP: £135 per club

Visit the Mizuno Golf website here