I can choose which weapons are to be visible on the back. Or I can deactivate it entirely, but it still looks weird, just like the original minigun animation with the "Magical Pocket". Maybe it is just because we are used to it that it does not seem strange. I think I'm already getting used to this 3D model, that's why I come here and ask for opinions.
In any case, since the weapon attachments configurations are handled by a text file, it could be easily deactivated, as an option in the config tool.