Handguns:
HK MK23, (Security)
HK USP Tactical, (Security)
HK P8/USP (Security)
FN FNX 45 (Security)
IMI Desert Eagle Mark VII (just for fun) (Insurgents)
IMI Desert Eagle Mark XIX (Security)
because they are cool and would fit perfect in this setting, besides that I think we need more handguns.
Rifles:
FAMAS G2 (Security)
Steyr Aug A1 (Security)
IMI TAR-21 (Security)
IMI Galil (Insurgents)
IMI Galil SAR (Security)
IMI Galil ACE (Security)
SG 553 (Insurgents)
STG44/MP44 (Insurgents)
MPs:
MP5k (Security)
MP5A3 with the cool Light-attachment handguard (Security)
MAC-10/11 (Insurgents)
Tec-9 (Insurgents)
MP40 (Insurgents)
Sterling (Securitiy)
B&T MP9 (Security)
HK UMP (Security)
SIG MPX (Security)
MGs:
M60 (Security)
MG34 (Insurgents)
MG42 (Insurgents)
"Sniper"Rifles/DMR:
M82A1 Barrett (Security)
M107 Barrett (Security)
M110 (Security)
HK G28 (Security)
L96 / G22 (Security)
HK PSG-1 (Security)
I think those guns would be a good addition to the game.