This type of weapon is not everyone can get just like that, because it is given only randomly after the full completion of the Tour "Two Cities", and again not everyone.... So I don't even know if you can get it in the game just by leveling up. But you can just buy it without going through any tours. You can buy the Killstreak sniper rifle here https://tradeoffers.tf/orders/440/Professional Killstreak Sniper Rifle.