Prototype grade Shadowstalker rail.
The item id for Rail 1 in unturned is 301. You can use this ID with the commands below to spawn the item, give it to a player or buy it on a modded economy server.
Size_X: 1
Size_Y: 1
Size_Z: 0.3
Amount: 1
Calibers: 1
Caliber_0: 14
Range: 6
Player_Damage: 5
Zombie_Damage: 25
Animal_Damage: 25
Barricade_Damage: 50
Structure_Damage: 50
Vehicle_Damage: 250
Resource_Damage: 250
Object_Damage: 75
Explosion: 54
Tracer: 50