For all the ways that Call of Duty: Modern Warfare 3 feels like an add-on for last year's game, it deserves some credit for shaking up the standard 1-55 progression system in a major way. Instead of unlocking every gun, throwable, and gadget just by leveling up, a huge chunk of MW3 items are locked behind new Armory Challenges.
Nearly half of MW3's guns are unlocked this way, and the only way to complete armory Challenges is to finish your three Daily Challenges. That's right, a challenge to complete challenges. You only get three Daily Challenges per day, but you can continue to grind Armory Challenge points by winning matches. It's a little confusing, especially for CoD fans who've been unlocking arsenals the same way for 20 years, but the new system has its upsides. You can now unlock a lot of the arsenal in whatever order you want—it just might take a little longer to get everything. That is, unless you tab over to Zombies mode.
Modern Warfare Zombies, it turns out, offers an alternative method for unlocking darn near every gun and throwable in the game. MWZ being built off Modern Warfare 2's DMZ mode means it shares one very generous rule: Whatever guns or grenades you can extract from the map are permanently unlocked in multiplayer.
Guns can be acquired a few ways in MWZ. The easiest is to simply extract out of a match with one of the contraband weapons the game supplies by default, but the more common ways are to buy them from marked areas on the map or find them as rewards for completing contracts. Once you have what you're looking for, all you have to do is make it off the map alive. The first gun I'll be trying this out with is the FR 5.56, MW3's version of the FAMAS that's locked behind the Armory.
For visual learners, CoD expert TheXclusiveAce covers this method for unlocks in the brief video below.
Funny enough, the absolutely quickest way to unlock every gun you don't have is to make friends with someone who does have them. If they drop the gun, you pick it up, immediately extract, and then it's yours. At this point I'd wonder if this is some big oversight that Sledgehammer Games will correct, except that this is exactly how DMZ worked too. As usual, it pays to play the non-core multiplayer mode.
The only catch for unlocking items via Zombies is that guns or throwables stored in a backpack will not count as an unlock—they have to be equipped to your main inventory. Don't be like me and assume you can unlock three grenades at once by stuffing them all in a pack.
Still, if you're maximizing your time every Zombies run could score you two new guns and throwables each. You won't find every Armory Challenge item on the Zombies map either. Some specialty attachments, killstreaks, and cosmetics will require the normal grind.
