Demolitions Class Weapon Class	Get rank 01
Sniper Class Weapon Class	Get rank 02
Create a Class	Get rank 03
Gun Challenges	Get rank 04
New playlists	Get rank 05
M40 Sniper Rifle	Get rank 06
Last Stand Perk Class 3	Get rank 07
Boot Camp Challenges 1	Get rank 08
M4 Carbine Assault Rifle	Get rank 09
UAV Jammer Perk Class 2	Get rank 10
Clan Tag	Get rank 11
Mini Uzi Submachine Gun	Get rank 12
Bomb Squad Perk Class 1	Get rank 13
Boot Camp Challenges 2	Get rank 14
M1911 Pistol	Get rank 15
Martyrdom Perk Class 2	Get rank 16
Boot Camp Challenges 3	Get rank 17
M60E4 Light Machine Gun	Get rank 18
Sleight of Hand Perk Class 2	Get rank 19
Operations Challenges	Get rank 20
Operations Challenges	get rank 21
Dragunov Sniper Rifle	get rank 22
Claymore Perk Class 1	get rank 23
Operations Challenges 2	get rank 24
G3 Assault Rifle	get rank 25
Iron Lungs Perk Class 3	get rank 26
Operations Challenges 3	get rank 27
AK-74U Submachine Gun	get rank 28
Double Tab Perk Class 2	get rank 29
Killer Challenges	get rank 30
M1014 Shotgun	get rank 31
Bandolier Perk Class 1	get rank 32
Killer Challenges 2	get rank 33
R700 Sniper Rifle	get rank 34
Eavesdrop Perk Class 3	get rank 35
Killer Challenges 3	get rank 36
G36C Assault Rifle	get rank 37
Overkill Perk Class 2	get rank 38
Killer Challenges 4	get rank 39
P90 Submachine Gun	get rank 40
Frag x 3 Perk Class 1	get rank 41
Frag x 3 Perk Class 1	get rank 41
Humiliation Challenges	get rank 42
Desert Eagle Pistol	get rank 43
Dead Silence Perk Class 3	get rank 44
Humiliation Challenges 2	get rank 45
M14 Assault Rifle	get rank 46
Humiliation Challenges 3	get rank 47
Humiliation Challenges 4	get rank 48
Barret Sniper Rifle	get rank 49
Humiliation Challenges 5	get rank 50
Elite Challenges	get rank 51
MP44 Assault Rifle	get rank 52
Elite Challenges 2	get rank 53
Elite Challenges 3	get rank 54
Commander Prestige Mode	get rank 55
Golden Desert Eagle	get rank 55

by:  http://videogamehelp.wordpress.com/2008/01/11/call-of-duty-4-modern-warfare/