Hello,I'm a fan of realistic guns in the real world.Although I'm not good at knowledgeable in the guns as some other users of this site are,but I'll do my best.
My favorite weapons
Pistol
Heckler & Koch MK23 SOCOM - .45ACP
Glock 18C (3rd Generation) - 9x19mm
Shotgun
Sub-machine gun
Heckler & Koch MP5-N - 9x19mm
Heckler & Koch MP5SD6 - 9x19mm
Heckler & Koch UMP45 - .45ACP
Assault Rifle
Colt M16A2 - 5.56x45 NATO
Colt MK18 MOD0 - 5.56x45mm
Heckler & Koch G36C - 5.56x45mm
IMI Tavor TAR-21 - 5.56x45mm
Norinco Type 56-1 - 7.62x39mm
If this rifle with rail grip,mount Eotech 552 holographic sight and M203 grenade launcher,the rifle is sure good.
Izhmash AN-94 - 5.45x39mm
Battle Rifle
Heckler & Koch G3A3 - 7.62x51mm NATO
Sniper Rifle
Remington M40 - 7.62x51mm NATO
Heckler & Koch PSG-1 - 7.62x51mm NATO
KAC MK11 MOD0 - 7.62x51mm NATO
McMillan TAC-50 - .50 BMG
Machine Gun
Saco M60 - 7.62x51mm NATO
FN M249E1 - 5.56x45mm NATO
Launcher
Colt M16A2 with M203 grenade launcher - 40x46mm