get like 30 60 kills with the gun you want the heartbeat with
The fourth level in Call of Duty Modern Warfare is No Russian (which can be skipped.)
Level 42
Get 15 kills with an assualt rifle that has a silencer equipped.
nothing
The Lieutenant Rank is at Level 34
Level 38
You unlock it at level 36.
You need to level and complete challenges
you have to be level 29
Heartbeat Sensor is not a Gun, it's a Attachment for all Assult Rifles. It is unlocked by killing 15 people with the silencer.
The TMP is unlocked on level 58.
level 4