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.
PS_MLRS_Missiles_Box.dat
GUID 3c617fdc78ca452da3fe18992819b20e
Type Magazine
Rarity Legendary
ID 10581
Size_X 6
Size_Y 3
Size2_Z 0.6
Amount 16
Count_Min 1
Count_Max 16
Calibers 1
Caliber_0 10703
Delete_Empty
Blueprints
[
{
CategoryTag "e1b8d81c8d5a43e99468170db4a9d385" // Ammunition
Operation FillTargetItem
InputItems this
Effect "03caec479dd2475c92e1c326e1720140" // Casing
}
]