Necromunda: Underhive Wars

You'll likely have this outstanding after all other operations achievements.

To speed through this first note that mission operation gang ratings are set based on the crew that complated the last mission, this can be abused. Hire a crew of two green juves and a leader on your main gang and strip them of all equipment. On the last mission of an operation use this crew and forfeit.

Select an easy operation next, enemy gangs will start on 900 rating and there should only be two. This will allow you to walk through missions with your main crew, who should all be level X with full Level V and VI gear by now. With only 2 other gangs you should be a free run at resources fairly often as well which further speeds this up.

Repeat this process on easy operations until you have 10,000.