Full Metal Jacket

Full Metal Jacketed Ammunition, known as FMJ Ammo, or FMJ is the only Ammo Mod that does not directly increase damage. It is also the only ammo mod with disadvantages to its use, resulting a trade off that must be weighed in by the user. FMJ increase the weapon's rate of fire by 15%, but at the cost a range decrease of 1. This may seem like a small loss, but its effects are instantly felt. Having a weapon with inherently less range than your comrades often results in many missed kills, which can lead to being underleveled. Many players are also reluctant to get any closer to enemies than they already must. However, their is one class that loves FMJ, the humble Marksman. His Sniper Rifle and Barrett already have the highest range in game, and he cannot even see far enough to strike targets at maximum range without allied assistance or sight upgrades. For all intents and purposes, FMJ has no side effects when used with Sniper Rifles, and since they are among the slowest weapons, the 15% speed increase has the greatest effect. One thing to avoid is using FMJ with the Crowbar, as it only has one range. This will result in a true melee weapon, and you will wind up taking unnecessary hits and standing quite literally under bosses. It will also remove its splash radius which will make it useless against hordes.