Simple Mod that Increases the range and damage of guns by 2X, and to compensate for that I made the ammo limits half (There will be a variant for EFLC Soon), you shouldn't be running out of ammo TOO often unless you waste it or go running and gunning.
(Guns have also been modified aside, like fire-rate and physics force, but again this was my personal setup for GTA IV and EFLC, so you have to deal with it).