over 3 years ago - [DE]Momaw - Direct link

It is intended that you only get mastery once for a kitgun chamber. It shows up under both Primary and Secondary categories in your Profile because of the way we track usage and stats,  which is our mistake. We're aware of the issue and are working on a fix but I don't have a timetable I can share with you yet.

As noted, for now, if it's really bothering you then the "zombie" kitgun entry will go away if you gain Affinity with the kitgun.