I just saw your post. Sorry about the delay in response;
I dropped a new round through the (obviously ample enough clearance) muzzle of the faux silencer before mounting it. No contact.
The thread pitch on the newer scrorpions (all the carbines, I think) is 1/2x28. This is the most common pitch and diameter for any threaded barrel. Earlier pistols were a different spec but I believe Tacticool also has this option.
If you consider that this 1/2x28 pattern is common to most caliber barrels and that this is essentially a shroud that extends aft of the barrels muzzle, you can conceive that enough clearance is there even for larger than 9mm rounds.
I might also add that I have safely put 200'ish rounds through the barrel since threading on the new shroud. No negative effect on accuracy or balance to report.