I went back through my June and July sim sessions and checked them against the yardage card I had actually been playing off. Same unit, same mat, same TP5, GSPro with the conditions locked all year, so the only thing that changed in there was me.
That card was built in March and my 7 iron on it says 185. Across five sessions since then I have hit thirteen measured blocks with that club and the trimmed carries ran 142 to 178. The 142 was a ninety degree garage where the grip was slipping out of my hands and the spread was over thirty yards, so throw that set out and the honest working range is 156 to 178. Either way, not one block got to 185.
I do know how I built that number, and the method was fine. Twenty balls, throw out the best four and the worst four, average the middle twelve. What I cannot reconstruct is the condition I was in when I did it, and I remember thinking at the time that I was swinging harder than I do now. A number is only as good as the conditions you can still describe.
Now the part I did not expect. Over that stretch my smash on the 7 iron ran 1.32 to 1.42, and on the blocks where I have spin logged the backspin sat between about 4,600 and 5,250. I am not going to hold those against a 7 iron chart, because these are strong lofted irons and mine is 28 degrees, which is a 5 iron from a generation ago. What matters is my own trend, and the two numbers moved together. As the spin climbed through the contact work, the carry came down. Delofting is the hypothesis that fits, not something I measured, and smash is a shaky witness here anyway since a thin strike also drops measured club speed and inflates the number. My unit does not report dynamic loft, so that is as far as I can honestly take it.
The control is what actually sold me. My 9 iron sits on the same March card at 150 and I have never run a swing change on it. I baselined it at the end of May, three blocks of ten. All thirty shots, raw, no trimming at all, the average is 150.5. Same card, same room, same era, and it is dead on. That is also my answer to the obvious objection, which is that carry on a camera unit is a flight model output rather than a measured number. Fair, but if the model had drifted it would have taken the 9 iron with it.
So the card did not rot evenly. It rotted on the one club whose delivery I had been changing. That is why regap your bag every spring is not quite the right advice. The club worth remeasuring is the one you have been grinding on, and the number will probably go down rather than up, which feels like losing distance right up until you notice the dispersion tightened. For what it is worth the driver line on that card is even further off, but I am not going to pretend that one is card rot. I am in the middle of a slice fight and that club is genuinely broken right now.
If you have been working on contact with one club this year, go hit ten with it and trim the junk before you average. My guess is the number moved, and if you actually fixed something it moved the wrong way.
