By now you've probably conquered the Gears of War 3 campaign and have moved onto the multiplayer modes.  We thought it would be helpful for those that have moved onto these fragtastic modes to know how the various weapons-related skins and executions are unlocked, so we present to you our Gears of War 3 Weapon Executions & Skins Guide!
Gears of War 3 Weapon Execution Unlocks
Every weapon in Gears of War 3 has a unique execution associated with it.  The execution is triggered when you hold down "Y" when approaching a downed enemy. All of these executions are available in the campaign, but you have to unlock them in multiplayer mode by getting a specific number of kills with each weapon. 
- LANCER RIFLE: 200 Kills
 - HAMMERBURST: 200 Kills
 - RETRO LANCER: 200 Kills
 - GNASHER SHOTGUN: 200 Kills
 - SAWED-OFF SHOTGUN: 200 Kills
 - GORGON PISTOL: 40 Kills
 - BOLTOK PISTOL: 40 Kills
 - BOOMSHOT: 40 Kills
 - DIGGER: 40 Kills
 - HAMMER OF DAWN: 40 Kills
 - MULCHER: 40 Kills
 - MORTAR: 40 Kills
 - ONESHOT: 40 Kills
 - SCORCHER: 40 Kills
 - TORQUE BOW: 40 Kills
 - LONGSHOT: 40 Kills
 - CLEAVER: 40 Kills
 
Gears of War 3 Weapon Skin Unlocks
Gears of War 3 weapon skins can be unlocked to customize the five primary weapons in the game, including the Lancer, the Hammerburst, the Retro Lancer, the Gnasher and the Sawed-off. The requirements for unlocking the skins are listed below. Note that our Gears of War 3 Weapons Skins Guide include the dlc/paid for skins at the bottom.
- CHROME LANCER: Earn the "Don't Hate The Player" achievement in "Gears of War."
 - CHROME HAMMERBURST: Earn the "Dirty, Dirty Horde" achievement in "Gears of War 2."
 - CHROME RETRO LANCER: Earn the "Domination" achievement in "Gears of War."
 - CHROME GNASHER SHOTGUN: Complete the campaign in all three "Gears of War" games.
 - CHROME SAWED-OFF SHOTGUN: Earn 1 achievement in "Gears of War" on PC.
 - CRIMSON OMEN HAMMERBURST: Earned the "Welcome to Beast Mode" achievement in "Gears of War 3."
 - CRIMSON OMEN RETRO LANCER: Earned the "Welcome to Horde Mode" achievement in "Gears of War 3."
 - CRIMSON OMEN GNASHER: Earned the "Welcome to Versus" achievement in "Gears of War 3."
 - CRIMSON OMEN SAWED-OFF: Earned the "Welcome to Arcade Mode" achievement in "Gears of War 3."
 - FLAMING LANCER: Unlocked for playing in the second week of the "Gears of War 3" beta.
 - FLAMING HAMMERBURST: Unlocked for playing in the first week of the "Gears of War 3" beta.
 - FLAMING GNASHER: Unlocked for playing in the fourth week of the "Gears of War 3" beta.
 - FLAMING SAWED-OFF: Unlocked for playing in the third week of the "Gears of War 3" beta.
 - GOLD LANCER: Have the Gold Lancer from "Gears of War 2" or play a multiplayer match of "Gears of War 3" in the first week.
 - GOLD HAMMERBURST: Have the Gold Hammerburst from "Gears of War 2" or play a multiplayer match of "Gears of War 3" in the first week.
 - GOLD GNASHER: Unlock the Veteran Gear achievement in "Gears of War 2."
 - GOLD SAWED-OFF: Unlock the Commando achievement in "Gears of War."
 - GOLD RETRO LANCER: Unlocked in "Gears of War 3" beta for getting 100 kills with the Gold Retro Lancer.
 - GOLD OMEN WEAPON SET: Reach level 100 in "Gears of War 3."
 - ONYX LANCER: Earn the Onyx Lancer medal in "Gears of War 3"
 - ONYX HAMMERBURST: Earn the Onyx Hammerburst medal in "Gears of War 3"
 - ONYX RETRO LANCER: Earn the Onyx Retro Lancer medal in "Gears of War 3"
 - ONYX GNASHER: Earn the Onyx Gnasher medal in "Gears of War 3"
 - ONYX SAWED-OFF: Earn the Onyx Sawed-Off medal in "Gears of War 3"
 - TEAM INSIGNIA RETRO LANCER: Earn the bronze Veteran medal in "Gears of War 3" (Play 100 multiplayer matches)
 - TEAM INSIGNIA LANCER: Earn the silver Veteran medal in "Gears of War 3" (Play 250 multiplayer matches)
 - TEAM INSIGNIA HAMMERBURST: Earn the gold Veteran medal in "Gears of War 3"
 - TEAM INSIGNIA SHOTGUN SET: Earn the Onyx Veteran medal in "Gears of War 3"
 
Gears of War 3 Paid/DLC Weapon Skins
- Arctic Camo
 - Blood
 - Child's Play
 - Deadly Cute (hot pink gradient)
 - Desert Camo
 - Desert Digital
 - Electric
 - Flower (pink)
 - Garish (flower print)
 - Haze (smoke effect)
 - Imulsion (glowing radiation effect)
 - Jungle Digital Camo
 - Ocean (waves)
 - Oil Slick (dark waves)
 - Rainbow
 - Team Pulse (red/blue depending on team)
 - Team Distress (red/blue cracks, depending on team)
 - Team Metal (red/blue, depending on team)
 - Thunderstorm (animated)
 - Tiger Stripe
 - Tribal
 - Urban Digital
 
Gears of War 3 Achievements Guide
Gears of War 3 Collectibles Guide
Gears of War 3 Weapon Executions & Skins Guide