I wanted to test whether you could wield guns in either hand however after swapping back (using the VSS) my gun seeming has been removed. The gun was acquired from a bandit if that matters

This is reproducible by simply putting a weapon in your offhand and attempting it aim/fire

Version: MW 2.0 Contagion v0.4.4.6 mc1.12.2
Mods Included:

The issue only happens with RPG-Hud installed? Which RPG-Hud version are you using?

Please close and ignore me, I don't have RPG Hud installed I mistook the other requests as the Modern Warfare mod github

Did you google the github page or how did you end up here instead?

Googled the issue, saw this github came up with a plethora of other Vics Modern Warfare mod issues that looked similar and thought I'd add a ticket, leapt to conclusions sorry

No problem. I hope your issue gets fixed.