Would it be easier to model such shape in CAD software like Plasticity? I kinda figured out how to make stock in general, but this one with shell holder have tricky shape, which is not easy to work with in subdiv because of the hole on curved surface. I tried to to it but can't avoid pinching and distorting overall shape…
This is the UV shells laid out in 3 sets. The first 2 are the main body outside and inside. The last one is basically the outside sleeves that I'm having the trouble with. The normals for just the third set Low and high poly next to each other, they're almost 99% identical save for a few smell edges