Grab a Handgun or a Machine Pistol to get the best mobility out of a Secondary Weapon or grab a Shotgun to get up close and personal. Launchers are great for disabling vehicles or killing anyone hiding inside a location.
Pistols

USP .45
Semi-automatic (single fire).
Unlocked: Default

.44 Magnum
Revolver.
Unlocked: Level 26

M9
Semi-automatic (single fire).
Unlocked: Level 46

Desert Eagle
Semi-automatic (single fire).
Unlocked: Level 62
Machine Pistols

PP2000
Fully automatic, close range.
Unlocked: Default

G18
Fully automatic, close range.
Unlocked: Level 22

M93 Raffica
3 round burst, close range.
Unlocked: Level 38

TMP
Fully automatic, close range.
Unlocked: Level 58
Shotguns

SPAS-12
Pump action.
Unlocked: Default

AA-12
Fully automatic, low ammo.
Unlocked: Level 18

Striker
Semi-automatic (single fire).
Unlocked: Level 34

Ranger
Double Barrel.
Unlocked: Level 42

M1014
Semi-automatic (single fire).
Unlocked: Level 54

Model 1887
Lever-action.
Unlocked: Level 62
Launchers

AT4-HS
Free fire or vehicle lock-on.
Unlocked: Default

Thumper x2
Grenade Launcher.
Unlocked: Level 14

Stinger
Vehicle lock-on only.
Unlocked: Level 30

Javelin
Location and vehicle lock-on.
Unlocked: Level 50

RPG x2
Fires unguided rockets.
Unlocked: Level 65