this is potentially true, though if there’s any flexion or breakage in the 3d print material, you’d probably some underpressure in the cartridge, not that such a thing would matter much, or a more troubling lack of accuracy, which may be significant even at this distance, but probably not. both especially if you’re not using hardware store parts. at a certain point, you do just kind of get into shinzo abe doohickey territory, with that sort of a thing, maybe easier just to use a couple pipes. on that note, you could also conceivably use a wipe-based suppression system with a classic hardware store four winds shotgun, OR a contained gas firing system, if you’re going the probably over-complicated 3d printing route, especially if you avoid some larger pressures which are probably unnecessary.
you really don’t need any advanced rifling or superior ballistics or anything, at the distance this guy was at. he could’ve even just used a knife, or a brick, or his hands, to be honest, especially since the CEO was not dressed in ballistic armor or protected in really any way. though I imagine the public would be somewhat less sympathetic to those methods since they’re seen as kind of brutal or psychotic, even if they have the same end result.
lol