Here is the full list of all 48 Necromunda: Hired Gun achievements.
Place the 5 bombs in a gap of less than 3 minutes in Escher Lab
Finish Avarus without using the grapnel
Kill 100 enemies while wallrunning
Wallrun 2500m
Trigger all mines on Steel way
Kill a Genestealer with a grenade launcher
Finish the Main Campaign
Finish Chapter 12
Finish Chapter 11
Finish Chapter 10
Finish Chapter 9
Finish Chapter 8
Take out 50 shields with the grapnel
Finish Chapter 7
Finish Chapter 6
Let Brickjaw live in Koloss 44
Kill 30 enemies with the Blast module
Kill 30 enemies with the Crush module
Fill one faction bar
Customize every aspect of a single weapon
Travel 5km using the grapnel
Kill an enemy with every weapon
Finish Chapter 5
Finish Chapter 4
Finish Kaerus without using any other weapons than the Ironfist
Finish a mission with an S rank
Open 20 chests
You have performed 100 Takedowns
Finish a mission using only special weapons
Kill 10 enemies in a row with headshots only
Find a +3 weapon
Upgrade one implant to the class 4
Complete the shooting training in Martyr's End
Buy an upgrade for your Mastiff
Finish Chapter 3
Kill 30 enemies with your Mastiff
Kill 60 enemies with the Perfect Aim module
Kill 100 enemies by using Augmetics powers
Kill 5 enemies in one use of Strength Booster
Amass 100.000 credits
You have killed 100 enemies with a headshot
Finish your first secondary mission
Finish Chapter 2
Kill Brickjaw in Koloss 44
Pet your dog in Martyr's end
Buy your first upgrade to the Rogue Doc
Finish Chapter 1
Finish all main missions with a rank of A or more