Mizuno JPX 800 Iron Review

Mizuno JPX-800 Pro Forged Iron Review

As was the case with the Cobra S2 Forged irons we reviewed last time around, the Mizuno JPX-800 Pro irons were also originally going to be part of our Best Forged Cavity-back review.  Just like the S2 forged, however, once we were deep into the testing process, it became clear that putting the Mizuno JPX-800 Pro along side the others in that review just didn’t make for a fair fight.

Part of the JPX series (which replaces Mizuno’s MX line) The 800 Pro is what could be called a transitional game improvement iron.  The head is less bulky than the standard JPX-800 (narrower sole, thinner top line), it features less offset, and visually, to me anyway, it looks a bit more refined than the average game improvement iron.

As far as shaft length is concerned, Mizuno hasn’t done anything sneaky (not that it’s a big secret anymore) to play to the distance crowd.  Standard lengths are inline with those of their MP-53 and MP-68 irons.  Because the JPX-800 is part of Mizuno’s game improvement series, it shouldn’t come as any real surprise that the lofts are 1° strong when compared to the MP-53 and 2° stronger than the MP-68.  For some additional perspective consider the lofts of the JPX-800 are actually, on average 1° weaker than those of the previously reviewed Cobra S2 forged, and by the time we get to the 7 iron (the club we use to conduct our performance tests), the JPX-800 is actually 2° weaker than the equivalent Cobra S2.

Although it’s a bit of an apples to oranges comparison, from a consumer education standpoint, it’s worth pointing out that there is a full 4° difference between the 7-iron in the Cobra S2 Forged set, and the 7 iron in Mizuno’s MP-68 set.  Obviously 31 does not equal 35, and yet they’ve both got 7s stamped on their soles.

Material Composition: 1025E “Pure Select” mild carbon steel (Grain Flow Forged)

Like the MP-53, the JPX-800 features Mizuno’s Triple Cut Sole (most visible in the leading edge grind), which helps to ensure consistent performance from a variety of lies.  Though Mizuno bills the JPX-800 Pro as having a thinner top line (in comparison to the standard JPX), several of our testers, and in particular the lower handicap golfers, told us that the top line was a bit too thick for their tastes.

How We Tested

The 6 golfers for whom we collected detailed performance data were asked to hit a series of shots on our 3Track Equipped simulators from aboutGolf.  As usual, testing was done at Tark’s Indoor Golf, a state of the art indoor golf facility located in Saratoga Springs, NY.  Detailed data for each and every shot for which we collected data is now viewable in the interactive portion of this review.  This data serves as the foundation for our final performance score.  As a supplement to our 6 performance testers, a subset of additional golfers were given the opportunity to test the Mizuno JPX-800 Pro and provide feedback in our subjective categories (looks, feel, perceived distance, perceived accuracy, and likelihood of purchase).  This information, which we also collected from our performance testers, is used as the foundation for our total subjective score.



From a distance perspective, the more traditional lengths and lofts do lead to decreased distance.  In direct comparison to the Cobra S2 forged, most of our testers lost between 3 and 10 yards of total distance.  Our highest handicapper, Dave, however, actually increased his raw distance average by 15 yards, which helped to offset the loses by our other testers.  Our thinking here is there is a point of diminishing returns when it comes to shaft length.  While better golfers can certainly adjust to an extra ¼”, the added length clearly works to the determent of guys still learning how to make consistent contact.

What’s interesting is that while shot for shot, the JPX-800 wasn’t as long as others we’ve tested, our testers were generally more consistent with their distances.  This general consistency of distance prevented the shorter shots from wiping out the longer ones.  In the end, while not quite S2 Forged numbers, our testers posted excellent overall distance scores with the JPX-800 irons.

MGS Distance Score: 96.84


It’s been our contention at MyGolfSpy that there’s not a ton of difference between golf clubs, especially those in the same category (in this case, forged game improvement irons).  Having said that, I was absolutely shocked that two of our testers (myself, and our 20 handicapper, Dave) posted exactly the same distance scores with the JPX-800 irons as we did with the S2 forged.

Dan was significantly more accurate (5 yards), while our other common testers showed vary little variance (±1 yard) from previous tests.  Our new tester Blake struggled a bit to hit the JPX-800 straight, although he was fairly consistent  (always left) with them.  His inclusion reduced the total accuracy score by about a point and a half.

With the outliers removed, we found that the average miss was less than 10 yards, which isn’t bad considering the average distance with the club was around 157 yards.  While there is plenty of room for improvement, we fully expect we’ll see a lot worse in the coming months.  In the end, the accuracy score, while not extraordinary, is more than respectable.

MGS Accuracy Score: 86.08

Consistency (Beta)

As we mentioned last time out, our consistency score is an attempt to quantify what the OEMs call forgiveness.  We think consistency is a better word, and this score basically illustrates how similar the results of one shot are to that of every other shot for a given golfer.  Our formula derives the total score from several factors (not just distance and accuracy).  The more similar the numbers from each shot, the higher the consistency score is.

This is only the 2nd time we’ve applied our consistency formula and the results are compelling.  In contrast to the results of our S2 testing, our testers were extremely similar to one another with respect to the consistency of the results they produced with the JPX-800 irons.  In fact, barely 5 points separated our worst consistency score (Mark at 85.4 from our best, Dan at 90.87).  Having said that, while the worst scores weren’t as low as they were last time around, the high scores weren’t nearly as high either. We derive our performance scores from the combined averages of our testers.  In this case, the result of that is a slightly lower, but still a very solid total consistency score.

MGS Consistency Score: 89.05

Overall Performance

I encourage you to take a look at the complete results of our performance tests on the Mizuno JPX-800 interactive page.  In addition to sorting all of our data by golfer, we’ve added the ability to filter by handicap and swing speed.

While this is only the 2nd time we’ve applied our new scoring system, the results are extremely compelling.  Because we’re so early into this new process, as much as we’d love each club to stand on its own, it’s impossible not to draw comparisons to the previously reviewed Cobra S2.  It’s somewhat remarkable, though I believe completely in the results, that after days of testing both irons, there’s a whopping .32 performance points between them.  The results certainly give some additional credence to the old adage that it’s not the arrow, it’s the Indian.

Like the S2, the JPX-800 is a very good all-around performer, which our tests suggest you should definitely be looking at if you’re  in the market for a forged game improvement iron.




We’ve talked about subjective scoring in our forum.  We’ve sent out surveys asking about how the individual subjective categories, and we’ve received comments that suggest we shouldn’t even bother including it.  We’ve taken everything you’ve told us to heart, which is why we’ve broken out our performance and subjective scoring, and provided scores for every category (down to 1/100th of a point).  I think the subjective “stuff” is a huge part of the buying process, especially in situations where the performance between clubs is extremely similar.  It’s impossible to discount the subjective entirely.

Another reason why subjective scoring matters is that, as I’ve mentioned before, there is very often a fundamental disconnect between how a given golfer thinks a club performs in his hands, and how it actually does.  Our performance tests have revealed these discrepancies time and time again, and continuously illustrate why club reviews based solely on one or two guys opinion, and that aren’t supported by any data beyond “I think” or “I feel”, are woefully inadequate.  The subjective perspective gives us an indicator of how closely perception is to reality.


Like the S2 Forged, the JPX-800 Pro finds itself stuck between a rock and a hard place, or perhaps more to the point, the JPX-800 (standard) and the absolutely beautiful MP-53.  Guys drawn to the game improvement space find the slimmed down “pro” version intimidating, whereas the guys drawn to what Mizuno calls game-enhancement clubs find the JPX-800 a bit bulky.  Some of our testers told us they were put off by the top line (too narrow for some, too thick for others), while others simply told us that it’s not what they expect from Mizuno.  Like the S2 the JPX-800 is a bit of a tweener club, that’s only beginning to find its market appeal.

MGS Looks Score: 89.07


More than anything else Mizuno is a company known for producing irons with unrivaled feel.  While our testers almost to a man rated the JPX-800 Pro higher than its competitors in this space, many who’ve hit Mizunos previously felt that the JPX-800 was a bit of a disappointment.

Of course, the guys moving from cast game improvement clubs had nothing but positive things to say.  In the end, most of our testers rated them as an 8, although a single 7, and a couple of 9s were also in the mix.  Brian, who didn’t take part in the detailed performance testing, told us that he thought the weighting of the JPX-800 Pro was absolutely perfect.

For my money, the JPX-800 pro offers very good feel, but if we’re being brutally honest, it’s not on the same level with those in the MP series.

MGS Feel Score: 87.54

Perceived Distance

Given that most of our testers hit the JPX-800 on the same day they hit the S2, it’s not a huge surprise that they perceived it as being the shorter of the two clubs – it is.  That said, we’re not talking about a tremendous difference in our tester’s minds.  Though a couple rated distance as a perfect 10, most of the 10s we saw for the S2s were replaced by 9s, and the 9s were replaced with 8s.  While the JPX-800 Pro is probably longer than our testers give it credit for, their for the most part match up with the results of our tests.

Tester Perceived Distance Score: 95.21

Perceived Accuracy

We’re uncovering an interesting trend with our recent tests.  It seems golfers are more accurate than they think they are.  This of course is the complete opposite of what we see with distance (where most golfers assume they’re 10 yards longer than our tests results prove).  With accuracy, golfers seem to have low expectations, with the actual results often being better than golfers give themselves credit for.

With respect to the Mizunos, it’ not like anyone (with the possible exception of Dan) was out there throwing darts, but they certainly performed better than some of the ratings (as low as 6) suggested.  As with our perceived distance scores, a number of 9s and even a 10 helped to offset the lower rankings.

Tester Perceived Accuracy Score:  87.54

Likelihood of Purchase

Likelihood of Purchase (or LOP as I like to call it) accounts for the smallest percentage of our subjective score.  It’s the closest MyGolfSpy gets to “demand” or buzz”.  We differ from others in that we don’t ask our testers to give us rating until after they have actually hit the club.  Our LOP question is simply this: “If you were going to replace the irons in your bag today, how likely is it that you would purchase the irons you tested today”?  Asking somebody if they like an iron is one thing.  Getting them to spend their money on them is an entirely different proposition.

Maybe it’s the clubs we’ve tested so far.  As I’ve pointed out several times already, the forged game-improvement space is golf equipment’s unchartered water.  Many golfers don’t know there are clubs in this space, fewer still are looking for them.  There could also be something in the  way we’re phrasing the question, but whatever it is, LOP numbers thus far are well below what we would have expected.

From a percentages perspective, LOP barely counts at in our scoring (5% of the subjective score), but we do like the insight it provides into how golfers really feel about the clubs they’ve just tested.  While most of the feedback we received on the JPX-800 pro suggests an “I’d think about it, but not on the top of my list” mentality, a couple of scores suggest a “not a chance in the world” mindset.  As per usual, those guys were largely balanced by a couple of testers who absolutely love the JPX-800 Pro irons.

Personally, I gave them a 7.  They’re a fantastic iron, but if I’m thinking forgiveness, I probably step down to the standard model, or perhaps look at something like a Ping K15.  If I’m inclined to go performance, feel, or looks, I probably step up to the MP-53.  Such is the fate of irons in this space I think.  They offer great balance, but probably not the best of anything.

Tester Likelihood of Purchase: 64.50

While clearly not a club that all of our testers are in love with, our golfers did rank the JPX-800 Pro measurably higher than the last forged game improvement club we tested.  Still, we’re almost certain there’s a lot of room for improvement here, and as we move through the year we’ll be testing clubs that we think will have broader market appeal.




This isn’t the first time Mizuno has had a club in this space (they’ve been doing it for years), but the fact that they’re no longer alone tells me that forged game improvement irons might be developing a broader market appeal.  Granted, the JPX-800 Pro,  a transitional iron “pro” enough to find its way into the bag of Charles Howell III, is probably at the extreme end of the category, but that only serves to remind us that there are plenty of guys playing less forgiving irons than they probably ought to be (yours truly included).

Again, I’m more inclined to play the MP-53s, but if you’re willing to sacrifice a bit of feel in exchange for increased forgiveness and assuming that the thicker top line isn’t a deal breaker, it’s difficult to find any real fault with Mizuno’s JPX-800 Pro.  With a more compact head than the average game-improvement iron, they really should be on the short list of any improving golfer looking to get a little more serious about his game.