This clandestine pistol is modified to:
-be electrically fired
-be extremely quiet
-shoot a deadly poison that emulates a heart attack and doesn’t show up on autopsies
-be capable of shooting a target without them realizing they’ve been shot
-work at 100 yards
Video of the hearing: [3:57] https://youtu.be/4m6dldvNECI?si=
A sabot solves a lot of the problems you list. It fills the barrel and imparts spin from the rifling. I also doubt the range claims, though.