Here is the full list of all 81 Lead and Gold - there are Gangs of the Wild West achievements.
Perform a Grand Slam (kill 4 players within a short amount of time) in any multiplayer match.
Kill 50 enemies using fanning.
Kill 3 enemies with a single dynamite blast.
Die 150 times.
Finish off 10 knocked down (KD) enemies in a single multiplayer round.
Kill 3 enemies within 12 seconds using fanning.
Revive a gangmate.
Score a long range headshot.
Win a match.
Kill an enemy.
Rack up 20 kills in a multiplayer round.
Rack up 30 kills in a multiplayer round.
Deliver 4 sacks of gold in a single multiplayer round.
Kill 3 enemies with a six shooter without reloading in a multiplayer match.
Perform at least 8 head shots in a single multiplayer round.
Play a multiplayer round without getting killed or knocked down and kill at least 4 enemies.
Play a multiplayer round without getting killed or knocked down and kill at least 8 enemies.
Catch 10 enemies in your traps during a single multiplayer round.
Kill 6 enemies caught in traps in a single multiplayer round.
Perform 10 headshots with the Buffalo rifle in a single multiplayer round.
During a multiplayer round, teammates kill 5 enemies tagged by you.
Tag 20 enemies during a multiplayer round.
Finish off 20 knocked down (KD) enemies in a single multiplayer round.
Revive 12 gangmates in a multiplayer round.
As the Gunslinger, deliver 3 sacks of gold and kill 12 enemies in a multiplayer round.
Kill 20 enemies with fanning in a multiplayer round.
Kill 15 enemies with dynamite in a multiplayer round.
Kill 25 enemies with the coach gun in a multiplayer round.
Shoot off 15 hats in a multiplayer round.
Win 30 matches involving sacks of gold.
Win 100 matches involving sacks of gold.
Win 100 powder keg matches.
Win 30 conquest matches.
Win 100 conquest matches.
Destroy 60 objectives.
Die 300 times.
Collect 8 sacks of gold in a Goldfever (COOP) match.
Play all release maps.
Revive 5 gangmates during a single game round.
Win 100 matches.
Be the player delivering the most sacks to base during a round. Repeat 3 times.
Kill 3 enemies caught in your traps during a multiplayer round.
During a multiplayer round, gangmates kill 10 enemies tagged by you.
Win 300 Matches.
Kill 250 enemies.
Kill 1000 enemies.
Kill 2000 enemies.
Shoot off 20 hats.
Shoot off 100 hats.
Shoot off 250 hats.
Attain rank 9 in a multiplayer match.
Destroy 20 Objectives.
Destroy 60 Objectives.
Destroy 180 Objectives.
Kill 20 enemies with your sidearm (Gunslinger's revolver not included).
Kill 60 enemies with your sidearm (Gunslinger's revolver not included).
Kill 180 enemies with your sidearm (Gunslinger's revolver not included).
Revive 30 gangmates.
Revive 180 gangmates.
Revive 720 gangmates.
Deliver 30 sacks of gold.
Deliver 180 sacks of gold.
Deliver 720 sacks of gold.
Conquer 30 zones.
Conquer 180 zones.
Conquer 720 zones.
Killl 30 enemies with dynamite.
Kill 180 enemies with dynamite.
Kill 720 enemies with dynamite.
Tag 40 enemies.
Tag 250 enemies.
Tag 800 enemies.
Trap 30 enemies.
Trap 180 enemies.
Trap 720 enemies.
Kill 300 enemies using fanning.
Kill 900 enemies using fanning.
Kill a developer.
Kill 7 enemies with headshots in a row (without dying)
Kill one and only one of each archetype in a row (without dying)
Shoot off 4 enemy hats in a row (without dying or killing them)