Get a mann co ticket Regardless of what source

select mann up and pick the hardest one

when you join a server normally a player will ask have you got brass beast, natascha and more. If you have these weapons say no i dont have that. If you give you the weapon Great and once you got all the weapons they asked you to equip.

NOW QUIT and join another server. Do this a lot of times and you can get a collectors weapon

Hp_Zeus
DR.BOOTY
Valve
Tf2 mercs
Merasmus
Sanic
ditto