This item is not included in any spawn asset, but it doesn't necessarily mean that it doesn't spawn naturally on any of the maps.
Fiveseven Mag 30rnd SS190.dat
GUID fff83a3bf394402d99ab0ed6496c2d77
Type Magazine
Rarity Rare
ID 59847
Size_X 1
Size_Y 2
Size_Z 0.2
Amount 30
Count_Min 1
Count_Max 30
Calibers 1
Caliber_0 56053
Spread 1.257
Shake 1.157
Recoil_X 1.057
Recoil_Y 1.357
Ballistic_Damage_Multiplier 1.11
Equipable_Movement_Speed_Multiplier 0.995
Tracer 48
Explosive
Explosion 55115
Blueprints 3
// Ammo Box
Blueprint_0_Type Ammo
Blueprint_0_Supplies 1
Blueprint_0_Supply_0_ID 58303
Blueprint_0_Build 55048
// P90 mag
Blueprint_1_Type Ammo
Blueprint_1_Supplies 1
Blueprint_1_Supply_0_ID 58313
Blueprint_1_Supply_0_Critical
Blueprint_1_Build 55048
// Five-seven mag
Blueprint_2_Type Ammo
Blueprint_2_Supplies 1
Blueprint_2_Supply_0_ID 58302
Blueprint_2_Build 55048