Mizuno JPX 800 Technology: Mizuno is kicking off 2011 with the launch of a new line they’re calling JPX. Completely new and exciting product will be introduced including drivers, irons and wedges. The JPX 800 Pro Iron is part of that new series. It is aimed towards the mid to low handicapper and incorporates traditional Mizuno feel with some new and exciting technology. In developing the JPX 800 Pro Mizuno tried to combine the forgiveness of the previous MX-200 irons with the feel and performance of the MX-300 line.
Like nearly all other Mizuno irons the JPX 800 Pro uses Mizuno’s Grain Flow Forging process to create a soft, solid and consistent feel. Mizuno also updated their Y-Tune weighting to help expand the sweet spot of the clubs over previous generations. Mizuno then developed a new process to expand the cavity milling in the JPX line. This allows a thinner clubface that results in a higher coefficient of restitution (COR) and Moment of Inertia (MOI).
Higher COR along with higher MOI equates to consistently longer and straighter shots, even on miss hits. The milling process also allowed Mizuno to progressively offer more forgiveness in the longer irons while maintaining traditional playability and shot making in the short irons.
To compliment the advanced performance of the clubs, Mizuno engineers also improved upon the feel of the JPX 800 Pro. Mizuno used Model Analysis and Harmonic Impact Tuning to improve the sound and feel of the iron at impact by inserting a specialized badge in the cavity of the iron. Lastly with input from touring professionals they incorporated a triple cut sole. The triple cut sole allows solid ball striking from nearly any lie while still maintaining the forgiveness of a slightly larger sole.
Test Results: I was interested in testing the improvements Mizuno has incorporated into their new line in the Miles of Golf Cluboratory. I did this by using TrackMan during a shortened version of a Miles of Golf Maxx Fitting hitting a #6 iron. I was able to try a variety of shaft options that are available through Mizuno’s Custom Department thanks to their Performance Fitting System Cart. You can see my results in the table below.
Ball Speed [mpg]
Launch Angle [degrees]
Spin Rate [rpm]
Accuracy [yards to flag]
*All shafts tested were in a stiff or equivalent flex
When testing the irons I immediately noticed that there was an increase of about 2 mph in ball speed over my current blade irons (Mizuno MP-68). However, the JPX 800 Pros still looked very similar to a blade or small cavity back from address. To me this is important, as I have always played a club with a smaller profile. The feel at impact was just as one would expect with the solid thump and feel of a forged iron.
The greatest impression the iron had on me however, was the forgiveness of the iron. Even the least accurate combination of the three I tested still averaged under 18ft from the pin at a distance of 175 yards. With my current blade set of irons averaging that close would be much more difficult. The JPX 800 Pro does a great job of maintaining the classic look and feel of a better players’ iron while incorporating much more forgiveness than ever before.
In analyzing the data I was surprised to see the differences in launch and spin between the different shaft options available from Mizuno. Changing small details such as shaft had a direct impact on the performance and feel of the club. If I had to choose the best for me it would have been the Dynalite. The combination of the lower launch and increased spin rate gave me an increased amount of control and consistency in the club. Not to mention the Dynalite’s weight is slightly lower than the other two, which is my preferred feel.
Summary: Overall the new JPX 800 Pro is a great new iron in an awesome new line from Mizuno. Increased ball speed over traditional irons make this a great option for anyone wanting to add a touch more forgiveness and distance to their game. Complimented with a proper fitting using Mizuno’s Performance Fitting System and the large amount of custom options available the JPX 800 Pro can be fined tuned for your game.
So did you really lose ~100yds with the KBS Tour shaft?
I assume the “76.7” yds with the KBS Tour shafts is a typo, otherwise I’d never buy them if they are going to cost me ~100yds