Mizuno JPX Hot Metal irons by generation
Mizuno has sold a new JPX Hot Metal iron every two years since the 919 in 2018. Each generation changed something, but not everything. Here's what changed, and which irons can fill a gap.
By Julien Levadoux. Specs from our iron catalogue, checked September 29, 2026. Each set's page names its source.
Download this guide as a PDF 2 pages, 106 KB. Print it or keep it on your phone.
Loft chart, club by club
Select a set to see its lies and lengths too.
| Loft | JPX 919 Hot Metal (2018) used from $314.99 | JPX 921 Hot Metal (2020) used from $384.99 | JPX 923 Hot Metal (2022) used from $754.99 | JPX 925 Hot Metal (2024) used from $654.99 |
|---|---|---|---|---|
| 4-iron | 20° | 19° | 19° | 19° |
| 5-iron | 23° | 22° | 22° | 22° |
| 6-iron | 26° | 25° | 25° | 25° |
| 7-iron | 30° | 29° | 28.5° | 28° |
| 8-iron | 35° | 34° | 33° | 32.5° |
| 9-iron | 40° | 39° | 37.5° | 37° |
| PW | 45° | 44° | 42.5° | 42° |
| GW | 50° | — | 48° | 48° |
| SW | 55° | — | 54° | 54° |
| LW | 60° | — | 60° | — |
| Used set, lowest price on Oct 26, 2026 | $634.99 | $604.99 | $754.99 | $654.99 |
— means the set has no club at that slot.
The short answer
No two Hot Metal generations are identical on paper. The 921 is 1° stronger than the 919 on every club (a 29° 7-iron against 30°). The 923 kept the 921's 4-, 5- and 6-irons exactly and strengthened the 7-iron to the PW (a 28.5° 7-iron). The 925 is another 0.5° stronger from the 7-iron down (28°) and listed 0.5° more upright from the 4-iron to the PW, with the same lengths as the 923 through the GW.
So for a missing 4-, 5- or 6-iron, a 921 and a 923 are interchangeable: same loft, lie and length. From the 7-iron down, buy the same generation as your set.
What changed, generation to generation
| Generation | What changed |
|---|---|
| JPX 919 Hot Metal (2018) to JPX 921 Hot Metal (2020) | Every club 1° stronger; drops the GW, SW and LW. |
| JPX 921 Hot Metal (2020) to JPX 923 Hot Metal (2022) | Lofts changed on the 7-iron (29° to 28.5°), 8-iron (34° to 33°), 9-iron (39° to 37.5°) and PW (44° to 42.5°); adds the GW, SW and LW. |
| JPX 923 Hot Metal (2022) to JPX 925 Hot Metal (2024) | The 7-iron to the PW 0.5° stronger; lies changed on the 4-iron (60° to 60.5°), 5-iron (60.5° to 61°), 6-iron (61° to 61.5°), 7-iron (61.5° to 62°), 8-iron (62° to 62.5°), 9-iron (62.5° to 63°), PW (63° to 63.5°), GW (63° to 64°) and SW (63° to 64°); lengths changed on the SW (35.25 in to 35 in); drops the LW. |
Which irons fit your set
“Identical” sets match yours on every club both make, so a single iron from one fills a gap in the other. “Same lofts” sets will fill the gap at the right loft, but check the lie or length difference with a fitter first. Either way, the head looks different from the rest of your bag.
| Your set | Identical loft, lie and length | Same lofts, lie or length differs |
|---|---|---|
| JPX 919 Hot Metal (2018) | None catalogued | None catalogued |
| JPX 921 Hot Metal (2020) | None catalogued | None catalogued |
| JPX 923 Hot Metal (2022) | None catalogued | None catalogued |
| JPX 925 Hot Metal (2024) | JPX 925 Hot Metal Pro (2024) used from $619.99 | None catalogued |
Missing one iron? Complete my set shows which clubs fill the gap, club by club.
Hot Metal, Pro and HL
Mizuno sells Hot Metal, Hot Metal Pro and Hot Metal HL in each generation. The Pro shares the standard lofts in a smaller head; the HL has weaker lofts. The tables here are the standard Hot Metal only, so check the full name on the listing. The 2024 versions have their own pages: the JPX 925 Hot Metal Pro (the same loft, lie and length as the 925 Hot Metal through the GW, so a single iron from one fills a gap in the other) and the JPX 925 Hot Metal HL used from $619.99 (3° weaker, a 31° 7-iron). Our source for the 921 lists no wedges after the PW, which is why the table shows none.
Mizuno's own spec sheets for these sets weren't available to us: every figure here comes from retailer spec tables, and the 921 and 923 are marked medium confidence. Mizuno lists two lengths for every club, its own measure and the USGA one (0.25 in longer); we show Mizuno's own length, the one on its spec sheets, for every Mizuno set, so the generations still compare like for like. A retailer listing a 7-iron 0.25 in longer is using the USGA measure. Treat half-degree differences with care, and if you have a Mizuno sheet, send it to us.
What we haven't catalogued
The 919, 921 and 923 Hot Metal Pro and HL versions, and JPX irons before the 919, aren't catalogued yet.