Indeed, I stand corrected. The Shocker has a different thread than the rest of the Smart Parts guns. The Ion, Impulse, Vibe and NXT Shocker all share the same threads. Kind of confusing since there are two different versions of the Shocker with different threads.
Even more considering what d-r0ck said. Wacky that if you ask what threads a Shocker has, you can get 3-4 different answers.
Impulse threads jumped to the NXT and beyond, all the way to GOG now. I think the Nerve used these as well. Since they eventually became SP's standard, they just called them Smart Parts threads. I think GOG is trying to get it renamed as GOG threads, but we'll see how that goes. May have been a private label NXT with cocker threads.
SFT & the old Shocker Sport had the same threads. Except for a couple private label SFT's with cocker threads.
If you go way back to the pneuVentures Shocker, that one was cocker threaded.