Beginner M40A3 Feedback

Hey guys, so this is my first project in Blender and i chose to model the M40A3 Sniper Rifle. Its not completed yet im just looking for general feedback on topology and so on. Ive started with Blender about 3 weeks or so and have followed the modeling tutorials from Blender Guru to get some overview, so im sure theres lots of stuff to improve.
Also side question: the body, barrel, bolt and trigger are all seperate objects but i want the trigger to be connected to the body, how would i go about this?

Below some screenshots and the .blend file.

Thanks for you feedback in advance.




Attachments

M40A3.blend (678 KB)