I asked tommybuilt what he did to make the combination of P30 slide and P30SK frame function.
According to him, there are no functional changes necessary to the gun to make it work.
The 'only' thing he did back then was to extend the front rail to cover the recoil spring assembly.
So what would we call this?😁 I mounted both the standard P30 slide and the P30L slide onto my SK and I would not hesitate to shoot them. I probably would not carry them since the dust cover leaves the recoil spring exposed. I carried my CZ 40P with a 75 slide in 9mm for years. It was essentially A long slide P01. The kydex holster needed some heat gun work but it was a great combo.