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