That situation appears in the leve Victor Charlie.
43
Level 80.
unfortunatly you cannot level up in cod 1 its a fish! jokes but seriously you cannot level up in (CALL OF DUTY 1).
Level 35
In MW3, it is unlocked at Level 80, and in BO; it is unlocked at Level 12 and costs 2000 COD Points
SAD.
You get it at level 56
Level 27, for 2000 cod points
Play and level up.
Get to level 55.
10 presteige, level 70= commandor general
There is no crossbow in MW3, but you can get the Crossbow in BO when you reach Level 33 and costs 2000 COD points.