COST: $239 (per iron).

TESTED BY: Jimmy Emanuel, Golf Australia Deputy Editor (GA Handicap 9.4).

MODEL PLAYED: JPX921 Hot Metal (4-iron to pitching wedge), with Nippon N.S. Pro 950GH NEO shafts and JPX921 Hot Metal Pro (4-iron to pitching wedge), with True Temper Project X LZ Blackout shafts.

FIRST IMPRESSIONS: Out of the box, the JPX921 Hot Metal looked as I expected. A forgiving, larger head with some clear Mizuno touches, while the Hot Metal Pro was noticeable for just how little offset it carried and how comfortable it looked behind the ball for a player used to much smaller irons.

On first hit the feel stood out for the standard model. Despite not being fully forged like the Forged and Tour models reviewed last month, the Hot Metal still possessed a solid and enjoyable feel coupled with a nice high and powerful ball flight. Moving to the Pro model, the feel was similar, if not a little better, while the ball flight was more penetrating, particularly with the long irons.

The other point worth noting was how much I enjoyed the blacked out look of the Hot Metal Pro, with black steel shafts, and all black grips. The difference is partly to help distinguish the models on the retail shelf, but was just flat out cool to my eye.

HOW THEY PERFORMED: Throughout my testing with both models, I was relatively unsurprised by every aspect of the performance, in the most positive way.

The standard Hot Metal option was powerful throughout the bag and the equal longest of the four JPX921 models alongside the Forged, with the Hot Metal Pro very close behind. Despite the long carries delivered by a high ball flight and optimal spin combination, the distances were very consistent and the forgiveness was outstanding.

Mis-hits saw little distance loss, and flew with a similar flight to a well-struck shot. But perhaps most pleasing was the solid feel that in no way could be described as ‘clicky’ like some other game improvement irons, not unsurprising for a company like Mizuno.

When it came to the Hot Metal Pro, my lack of surprise was due largely to the fact that I preferred this model more than the standard and through its slightly lower flight and more workable ball flight.

As mentioned previously, the look of the Hot Metal Pro was perhaps the area that did catch me off guard having not tested the previous iteration. Straddling perfectly between a player’s cavity and a forgiving game improvement iron, it is no surprise that players like Paul Casey have opted for this as a long iron replacement in the past.

The lower ball flight suited my eye, and partnered with an impressive level of forgiveness, makes the Hot Metal Pro a great option for players on the improve moving from easier to hit models to irons designed for a better player, or players who have lost some clubhead speed but still crave a look closer to what they may have used in the past.

This ball flight and forgiveness combination really stood out to me in the long irons, where I really enjoyed taking the Hot Metal Pro 4-iron off the tee on tighter tee shots or when approaching longer holes.

In fact, both models’ mid to long iron performance was the highlight for mine, which should excite the players each are aimed at, which takes nothing away from short irons that although larger than what I am used to were very capable of every shot needed over the course of a round.

Despite the JPX921 Hot Metal and Hot Metal Pro irons as full sets not being aimed at a golfer like myself, I really enjoyed both for what is arguably their main focus when it comes to the design and performance.

The standard model produced significant distance increases throughout the bag with consistency and forgiveness that made iron play somewhat automatic, if lacking the ability to hit varied trajectories.

The Pro provides similar benefits in a good looking, lower flight model that was my personal favourite.

Unsurprisingly, Mizuno has refined the feel in its game improvement options to be closer to that of its fully forged models, and this combined with distance makes the company’s latest irons in this category its best I have experienced first-hand throughout my time in the golf industry.

Coupled with Mizuno’s top class fitting system and the previously tested Tour and Forged, there really is a JPX921 iron for almost every golfer.


SUITABILITY: Fitting into the game improvement category, the Hot Metal irons will suit mid to high handicap players looking for distance, forgiveness and increased launch, with the Pro option offering similar performance characteristics in a more compact, lower offset look preferred by better players.

SHAFTS: The Mizuno Custom Program offers one of the widest selections of no upcharge shafts and grips in the industry relying on the Mizuno Shaft Optimizer and high-tech Swing DNA software.

LEFT-HANDED: The JXP921 Hot Metal is available in left-handed, while the Hot Metal Pro is offered in right-hand only.

MIZUNO SAYS: The JPX921 Hot Metal irons deliver Mizuno’s fastest ever ball speeds, a piercingly straight ball flight together with controllable landing angles.

The JPX921 Hot Metal represent the third generation of Mizuno irons to utilise the resilience of Chromoly – R&D generally accepts that any new technology needs three generations to reach near-optimal performance.

The JPX921 features Mizuno’s most complex face geometry to date, to produce additional energy from the clubface; the Hot Metal Pro version offering a more compact profile with reduced offset.

The use of Chromoly 4140M and a re-engineered ‘CORTECH’ face, now 0.2mm thinner across the centre point, creates exceptional ball speeds. These are further enhanced by the ‘Seamless Cup Face’ featuring a variable thickness sole design that allows the leading edge to act as a hinge, generating greater flex.

Three additional sound ribs produce a more solid sensation at impact while extreme perimeter weighting and toe bias in Mizuno’s Stability Frame help to deliver greater consistency from off-centre strikes.

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