@Cain,
I'm still not sure you are using a good example, in that Ghouls have a body of 7 - higher than maximum normal human. With that in mind, you are correct - you realistically can't one shot them with a pistol.
Gun adept has an Ares Pred, he can get 9 hits (6 accuracy, +2 for smartlink, +1 for Enhanced Accuracy). Assume he is using normal ammo - so that is 17P DV -1AP
A ghoul has Reaction of 5, Intuition of 4, so 9 dice on the defense - lets assume the pistol adept fires an SA burst, reducing that to 7 dice.
So, on average, 2 hits. Reducing the attack to 15 DV -1 AP
Armor Jacket is 12 dice (down to 11), body is 7, so 19 dice, so about 6 hits, taking it down to 9 DV - which leaves it still up and about, although with a -3 DP modifier.
Even APDS ammo only means they take about 10-11 DV - which is still below their Condition Monitor of 12.
Now, try that against more "normal" opposition.
Professional Rating 1 - Street Scum:
Reaction 3, Int 3, so 6 dice to dodge, -2 for the SA burst, yields only 1 hit, and their Armor Vest and body of 4 gives them 12 dice to soak, which is 2 more hits, so your 17P damage is only reduced to 14P, which is well above their Condiition monitor of 10. One shot, one kill.
Professional Rating 2 - Corporate Security
Reaction 4, Int 3, so 7 dice to dodge, -2 for the SA burst, yields only 1 or 2 hits, and their Armor Jacket and body of 4 gives them 15 dice to soak, which is 2 or 3 more hits, so your 17P damage is only reduced to 12P, at best, which is still above their Condiition monitor of 10. One shot, one kill.
Professional Rating 3 - Police Patrols
Is exactly the same as above
Professional Rating 4 - Organized Crime
Is exactly the same as above
Professional Rating 5 - Elite Corporate Security
Reaction 7, Int 5, so 12 dice to dodge, -2 for the SA burst, yields only 3 hits, and their Full Armor and body of 6 gives them 23 dice to soak, which is 7 more hits, so your 17P damage is only reduced to 7P, which leaves them more than half dead, but still kicking.
If you want to one-shot the Ghoul, you want APDS and full auto. The reduction in armor and dodge pool should drop him.
Gun adept has an HK227, he can get 9 hits (6 accuracy, +2 for smartlink, +1 for Enhanced Accuracy). Assume he is using APDS ammo - so that is 16P DV -5AP
A good has Reaction of 5, Intuition of 4, so 9 dice on the defense - Full auto reduces that to 0.
Armor Jacket is 12 dice (down to 8 ), body is 7, so 15 dice, so about 2-3 hits, taking it down to 13-14 DV - which both are above its Condition monitor of 12.
Compared to 3e, it is laughable, in that a single shot from a Heavy Pistol from a gun adept would
easily kill a Ghoul in an armor jacket in one shot. AND in 3e, even if somehow I didn't kill it in one shot, I could shoot again in the same Initiative Pass. So for me, the idea that 5e is "a more deadly combat system" is sort of funny
Caveat - again, I didn't play 4e, so it may very well be more deadly than that.