Master-at-armsG 30

Brace yourself for some grinding here. 18 weapons in total, 6 rifles, 6 pistols, and 6 secondaries.

Mastery for the rifles requires getting 50 headshots at 100+ meters away. In the case of the M1 carbine you may want to modify it to perform better at long range, but for the other 5 rifles they’re very capable of 100m headshots from the very start. (This is the easy part.)

Pistol mastery requires 50 Ghost kills. Once again, this is pretty easy for 5 of them. Just put a suppressor on and shoot an isolated enemy, ideally with a headshot. You can even save, shoot, reload the save, and shoot again, grinding out all 50 kills on one enemy. The Webley revolver can’t be suppressed, so the best way to do this is with sound masked kills. You may want to camp out near an enemy and a generator, give it a kick, make a save, shoot while you’re sound masked, and reload as necessary. It’s hard to get unsuppressed pistol ghost kills during organic play.

Getting mastery on secondary weapons is simple, just a grind - 150 kills per weapon, so 900 across the 6 weapons. Get yourself in big, nasty firefights, get it gradually over time, blast the same couple guys and keep reloading a save, it’s up to you. No real trick to it (aside from turning down the difficulty so you can be more reckless) you just need to get kills.

Achievement will unlock as soon as you master all 18 base game weapons.