Weapons in this pack:
Hammer
Kitchen Knife
Katana
Crowbar
FN Five-seveN
Colt Detective Special
Beretta 93R
IMI Desert Eagle (Gold Tint)
Intratec Tec-9
Steyr TMP
Heckler & Koch UMP
MAC M-10 (Silenced)
Mossberg 500
Winchester 1897
Savage Sawn-Off
Daewoo USAS-12
Saiga 12k
Sturmgewehr 44
GIAT FAMAS G2
Saco M60E4
Remington M40A5
SVD Dragunov
Walther WA2000
V40 Mini
M67
Impact Grenade
M202 FLASH
Colt M16A4

This is a general weapons pack for GTA IV and EFLC. Every weapon in the game can be replaced with this pack. A tutorial will be listed below.

To install weapon mods, install OpenIV. Then, specify where your copy of GTA IV or GTA EFLC is on your hard drive. After OpenIV finds your copy of GTA IV, navigate to pc>models>cdimages>weapons.img (weapons_e1.img for The Lost and Damned, weapons_e2.img for The Ballad of Gay Tony). Replace the .wdr and .wtd files for basegame weapons with the modified files, and upon boot, you should see the modified weapons. The internal file names and their in-game names will be listed below.

cj_rpg_rocket - Rocket (NOT the RPG, just the rocket. It can be spawned with a trainer in the protagonist's hand, and it will act like it was fired out of the launcher.)
rpg - RPG
w_cue - Pool Cue (Full-length, has no HUD icon. Must be spawned with a trainer)
w_knife - Knife
w_bat - Baseball Bat
w_glock - Pistol
w_eagle - Combat Pistol
w_uzi - Micro SMG
w_mp5 - SMG
w_shotgun - Pump Shotgun
w_pumpshot - Combat Shotgun
w_ak47 - Assault Rifle
w_m4 - Carbine Rifle
w_rifle - Sniper Rifle
w_psg1 - Combat Sniper
w_molotov - Molotovs
w_grenade - Grenades

Weapons exclusive to The Lost and Damned:

w_e1_cue - Pool Cue (Full-length, must be spawned with a trainer)
w_e1_cuehalf - Pool Cue (Half-length, can be obtained without a trainer)
w_e1_cz75 - Auto 9mm
w_e1_sawnoff - Sawn-Off Shotgun
w_pumpshot - Combat Shotgun (Different from the model in the base game)
w_e1_sweeper - Assault Shotgun
w_e1_grenade - Grenade (Different from the model in the base game)
w_e1_glauncher - Grenade Launcher

Weapons exclusive to The Ballad of Gay Tony:

w_e2_44amag - Pistol .44
w_e2_p90 - Assault SMG
w_e2_uzi - Gold SMG
w_e2_aa12 - Automatic Shotgun
w_e2_aa12_exp - Explosive Shotgun
w_e2_m249 - Advanced MG
w_e2_dsr1 - Advanced Sniper
w_e2_grenade - Grenade (Different from the model in the base game and TLaD)
w_e2_stickybomb - Sticky Bombs
w_e2_glauncher - Grenade Launcher (Different from the model in TLaD)
w_e2_rocket - RPG (Different from the model in the base game and TLaD)