My m8 recently started playing Cod4 and i was sick of playing with the ak + m16 when i was round there so i snooped out most of the weapons unlock codes for v1.5
There are a few missing but just search from offset 0CC19000 and it'll be in the top in the results list
*note may take longer if you most/all your challenges are at 0
All offsets are 4 bytes
EXP
0CC19690
M16 MARKSMAN
0CC1999B0
AK47 MARKSMAN
0CC199B8
AK47 EXPERT
0CC199BC
M4 MARKSMAN
0CC199C8
M4 EXPERT
0CC199CC
MP5 MARKSMAN
0CC19A00
SKORPION MARKSMAN
0CC19A08
MINI UZI MARKSMAN
0CC19A10
MINI UZI EXPERT
0CC19A14
M249 SAW
0CC19A50
RPD MARKSMAN
0CC19A58
M21 MARKSMAN
0CC19AF0
M21 EXPERT
0CC19AF4
M40A3 MARKSMAN
0CC19AFB
M40A3 EXPERT
0CC19AFC
M60 MARKSMAN
0CC19A60
M60 EXPERT
0CC19A64
W1200 MARKSMAN
0CC19AA0
SVD MARKSMAN
0CC19B00
G3 MARKSMAN
0CC199C0
AK74u MARKSMAN
0CC19A18
AK74u EXPERT
0CC19A1C
M1014 MARKSMAN
0CC19AAB
R700 MARKSMAN
0CC19B08
M14 MARKSMAN
0CC199D0
M14 EXPERT
0CC199D4