I found this hecking interesting article about Behind the Scenes of 'The Gun'. There's a fun information about what happened during the filming, when they especially made the last pier scene in "The Gun" episode. Also some unseen behind the scenes pictures.
The article also kind of described what MacGyver stuff their own studio kept inside, all the sets etc...
The filming day was told very detailed and what happened after every camera cut. I liked mostly about the story, when every time Richard was suppose to speak his line on the camera, some airplane flew above their head interrupting the scene all the time or some seagulls screaming became louder and louder
There was also little mention, why there was same actor playing couple different characters in the series
ChEcK iT oUt
http://www.rdanderson.com/macgyver/features/1990macset.htm