not a gun guy, but I'm just gonna say that once I read a book where a guy used custom loaded 22s fired from a chambered down pistol so that there would be no chance at ballistics matching anything. the round would be too mangled. additionally, the loads were subsonic so his homemade suppressor would be even more difficult to recognize as a gunshot by anyone nearby. they would hear something for sure, but nobody would mentally register it as a gunshot.
this configuration resulted in a low power, close range single action that would require him to manually work the action after every round and make it easier to keep track of his brass.
he did all this because it was never going to be used in a real fire fight. he was only using it to cap unarmed people who were caught completely off guard.
when I saw the video, the first thing I thought of was this book I read like 20 years ago.