I have recently added a bit more detail to this model. From looking at my reference images it was clear that the cap was a bit wrong so I have sharpened it up which has made it look a bit better and have also put in the baffle (all be it a simple cylinder). I have also unwrapped the model and have started with the texturing as well, I am playing around with a carbon fibre texture for the cap and strap but I am finding it a bit annoying trying to get a realistic shader to represent stainless steel.
Before I continue with the texturing I think I will go back and complete the modelling. All thats needed are some little bolts, clips and springs and then it should be good to go!