The major power factor for IPSC/USPSA back in the day was 175pf. Which is well over stock SAAMI spec .38 Super and 9mm loads. Enough problems came up to where you had terms such as ".38 Super face" when a 1911 extractor came out your way. It was tough on stock guns so S&W did the right thing to develope and gun and cartridge that would handle the pressure of such a load. But that left a lot of guns out there that wouldn't, so the easy fix was to only allow it in Open Class where there were mostly all custom built guns. Then make Limited Class .40cal and up for major and anything under score only minor at the 125pf. They have since gone down to 165pf for major and you are now seeing 9mm major in Open Class. I think S&W missed the boat when they didn't pursue more of a LE market for the .356TSW, easily surpass the .357sig and would give them the high capacity they were looking for, coulda, woulda, shoulda.