Lasor, no arguement from me on the reason for the PLASTIC (polycarbonate) tip
But
http://www.google.com/search?hl=en&lr=&oi=defmore&defl=en&q=define:PolycarbonateGod I love Google
Definitions of Polycarbonate on the Web:
A type of
plastic used in sign faces, noted for its heat-resistance andimpact strength
Engineering
plastic used for the shell and substrate of Sony magneto optical disks
A hybrid word meaning "many in composition with carbon atoms." Polycarbonate resins feature many chains of molecules linked to one another, forming a hard thermo
plastic with a great resistance to impact and softening. Polycarbonate has been reported to be 50 times stronger than acrylic.
Rigid
plastic that is easy to handle and can be cut to size. It is less susceptible to breakage than glass products. Scratches very easily but can be supplied with mar resistant coating.
Plastic that is very impact-resistant, and is thus sometimes used for spectacle lenses and frames.
Polycarbonates are a particular group of thermo
plastic. They are easily worked, mold, and thermoformed; as such, these
plastics are very widely used in modern manufacturing. They are called polycarbonates because they are polymers having monomers groups linked together by carbonate groups (-O-CO-O-) in a long molecular chain

I love to argue, my wife says I would argue with God
I worked dental in the Air Force for 20 years, we used polycarbonate crowns with some patients, we all used to call them plastic crowns