Mintage:
Circulation strikes: estimated 5,000,000
Proofs: estimated 4,000,000

Designer: Obverse by Gilroy Roberts; reverse by Seth Huntington

Diameter: ±31 millimeters

Metal Content:
Outer layers - ±80% Silver, ±20% Copper
Center - ±79% Copper, ±21% Silver

Weight: ±178 grains (±11.5 grams)

Edge: Reeded

Mintmark: "S" (for San Francisco, CA) centered above the date

Image courtesy of 

Varieties:

Notes:
The Silver Bicentennial Half Dollars were sold in 3-piece sets along with the Silver Clad Washington Quarters and Silver-Clad Eisenhower Dollars.  Mintages are approximate - 11,000,000 sets were struck and sold until 1982, when sales were halted.

Sources and/or recommended reading:
"The PCGS Population Report, August 2000" by The Professional Coin Grading Service