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.
ShAK 12.7 Mag.dat
GUID fa14352cdcc144be83957a941637358c
Type Magazine
Rarity Rare
ID 59205
Size_X 1
Size_Y 1
Size_Z 0.3
Amount 10
Count_Min 5
Count_Max 10
Calibers 1
Caliber_0 56174
Spread 1
Shake 1.2
Recoil_X 1.2
Recoil_Y 1.1
Equipable_Movement_Speed_Multiplier 0.995
Tracer 48
Explosive
Explosion 55075
Blueprints 3
// Ammo Box
Blueprint_0_Type Ammo
Blueprint_0_Supplies 1
Blueprint_0_Supply_0_ID 59210
Blueprint_0_Build 55048
// ShAK 12.7 Mag
Blueprint_1_Type Ammo
Blueprint_1_Supplies 1
Blueprint_1_Supply_0_ID 59205
Blueprint_1_Build 55048
// ShAK 12.7 Mag 20rnd
Blueprint_2_Type Ammo
Blueprint_2_Supplies 1
Blueprint_2_Supply_0_ID 59207
Blueprint_2_Supply_0_Critical
Blueprint_2_Build 55048