Thats a good sumation really, makes it a heck of a lot clearer than it was. OK a rethink of a couple of points.
If the S&W 500 hits for 375-400, and a headshot gives a multiplyer of 1.2x, 60% perk bonus and I'd guess the same zed time damage bonus as the sharpshooter headshot bonus of 50%. With that we are looking at a minimum damage of 1080 damage... that will be a phenominal amount of damage per shot for a pistol.
I would say this thing either needs a slow rate of fire, like half the speed of the deagle, to go with its long reload, and a very limited supply of ammo.
Although preferably I think remove the ZEDtime bonus and give the gunslinger reduction to near immunity to on screen effects. (Not total immunity because the on screen effects do help identify where a threat is) (Expansion on NoGlory's idea
)
E.g. when a stalker hits him, his screen doesn't go red, doesn't shake when hit by a siren, bloat acid wont block his view, etc. This does also fit into his run and gun ideology, and ZEDtime is fairly infrequent, so this would be a benefit he wiould see more use of.
This means in the above model he can still do 720 damage per headshot, which is still a heck of alot for a pistol
The levelling would also be a pain as again ZEDtime will be a real pain to gets kills in, since most times there are no other specimens in sight when it triggers. This number would have to be either really low, or another method needs to be used. Could make it kill target specimen after being wounded by them.
The role this would give the gunslinger/pistoleer/handgun specialist is when the team needs to get out, he will be one of the better classes to punch a hole for escape.