This mod tweaks weapon attributes to make them behave more like they should, without overdoing it or altering the difficulty curve much. Significant changes include extended effective range for most weapons, and altered damage, rate of fire and magazine capacity for some others. The net result of all this is the weapons are more logical in terms of specs and capabilities, are more satisfying to use and - under the right circumstances - are more effective, both in the player's hands and in the hands of their opponents.

Using this mod with a gamepad control setup may result in unexpected results due to the different way aiming and targeting is handled, so I recommend using this mod only with a keyboard and mouse control setup.

Summary of changes

* The effective range of almost all of the weapons has been extended significantly. By default, effective range on pretty much anything but a sniper rifle drops off suddenly at a relatively short distance. This would, all too often, leave the player able to clearly see a target but not hit it. While before a bullet fired from an assault rifle could hardly cover the length of a city block before disappearing into thin air, assault rifles can now be used to target enemies out to a few hundred meters away.

* Magazine capacities of certain weapons have been changed to reflect their magazines' actual dimensions (the Pump Shotgun's magazine is too small to fit 8 shells, it now holds 4, likewise the Micro SMG which now holds 32 rounds instead of 50) and changes in caliber (the Pistol, despite appearing to be a 9mm Glock 17 at first glance, is actually a Glock 22 in .40 S&W, the stats have been updated to reflect this.).

* The damage of certain weapons has been increased, while the physics force of most weapons has been decreased (the only exceptions being the shotguns, their force has been increased slightly). Appropriately, given their calibers, the Assault Rifle (AK-47) is now more powerful than the Carbine Rifle (M4A1), though it is slightly less accurate.

* The accuracy of some weapons has been increased slightly, while others' accuracy has been reduced slightly. This is all very subtle, the biggest changes in this regard were made to the shotguns, and even those were only slight, to avoid creating issues with AI targeting.

* The rates of fire of some weapons has been adjusted. The Desert Eagle's rate of fire has been reduced to simulate Niko absorbing and compensating for the weapon's heavy recoil, while the rates of fire of the Micro SMG, SMG, AK-47 and M4A1 have been increased, with the M4A1 having the highest rate of fire. Previously, a bug caused the SMG's blindfire rate of fire to be noticeably slower than its normal rate of fire, this has been compensated for, so now the weapon fires at exactly (or almost exactly) the same speed however it's used.

* The shotguns have been changed significantly. Both the Pump Shotgun (the short one) and the Combat Shotgun now have slightly smaller capacities (4 and 8 respectively), but they are significantly more powerful, moderately more accurate and have extended range, particularly so in the Combat Shotgun's case. Pre-modding, I found the shotguns to be rather useless compared to SMGs and assault rifles, but now they're utterly deadly in close quarters and the combat shotgun eats cars for breakfast.

* The maximum ammo capacities of most weapons has been reduced to 10 magazines' worth or less (For example, the AK-47's maximum ammo capacity is 300). On the one hand, it's still unrealistic, but not it's as excessive as before. On the other hand, it forces you to resupply a bit more often, but you won't be running out of ammo all the time unless you waste it.

Installation

First, you must modify your copy of the game so it will accept modified files. For details on how to do this, see this topic on GTAForums.com: http://www.gtaforums.com/index.php?showtopic=397149

Next, extract the WeaponInfo.xml file to the following directory:

\Grand Theft Auto IV\common\data\

Make sure you back up the existing file in case you want to revert to it!

Addendum

I highly recommend the Real Recorded Gun Sounds mod by jclewis as a companion to this mod.