Some more Behind the Scenes insights from Andrew Bikichky...
Andrew's favorite character in the show is Castle. He made an appearance in “To Live and Die in LA’ from Season 3. His favorite Castle scene is the doll breaking scene in the episode written by Terrence Winter, “Secret's Safe With Me”. In that episode Stana and Nathan did the "handshake" 2-4 times to get it correct.
The crew generally knows two weeks in advance the locations for their filming.
The mood on set alters depending on the scene being shot, for example the hanger scene in "Knockout", the funeral and Montgomery's shooting.
Depending on the scene, Stana, Nathan, Jon and Seamus have real guns however they do not use real bullets. Sometimes the crew makes bets on the wrap times and Andrew says he is pretty accurate.
Here are some of the photos Andrew has tweeted.