silvery saucer crossing overhead 200-300 feet up clear sky tipping side to side no sound

I was walking down a dirt road with grandfather and other family checking pecan trees, which may make this october and not september, but, I climbed pasture to go over and check a single tree out in ten acre hayfield. 
As I was looking up at the tree, facing to the east, while the others were walking on down the road to the west I saw something break the horizon over a treeline about 1/2 mile away.  It passed somewhat over me and as quickly as I could turn to watch it, it was gone.  
It was like brushed stainless steel, shaped like two pie pans put together with no lip and as it passed over it was tipping from side to side.  
I asked the others if they saw it go over, and my grandfather's response was "I didn't hear anything", which is when I realized that I had not either, no sound.  
It was a clear Sunday afternoon, blue sky, no clouds. I can visualize it as clearly as if it were yesterday. I know it was not like any aircraft that I had ever seen. 
It was approximately 200-300 feet up and would have measured 30-40 feet in diameter based on the perspective from the tree in the field. The speed was such that it traversed the 3/4 mile total sighting in a matter of less than 10 seconds.
Witness indicates that date of the event is approximate.  PD