Nice work!
The trickiest part for me is always that little detent and spring for the front takedown pin. Getting that little bugger in place without launching it into orbit takes focus.....grin
Buddy showed me the clevis pin trick, which makes that a piece of cake...
https://www.youtube.com/watch?v=XJNaTjvQaVQNow, if you've got a trick for pinning that #$%& gas block/tube, I'm all ears.