Kennedy half dollars from 1965 to 1970 contain 40% silver with 0.1479 troy ounces of actual silver weight. The coins have a clad composition: an outer layer of 80% silver/20% copper bonded to an inner core of approximately 20.9% silver/79.1% copper, averaging 40% silver overall.
These are often overlooked by stackers because 40% silver is less intuitive than 90% silver and the per-coin silver content is lower. However, they trade at very low premiums — sometimes even below melt — making them one of the most undervalued silver products on the market. A $1,000 face value bag of 40% Kennedy halves contains approximately 295 troy ounces of silver.
The 1970-D is the key date of the 40% series with a lower mintage than other years. All dates in this range contain silver, including the bicentennial 1776-1976 variety which was produced in both 40% silver (collector sets) and clad versions. From 1971 onward, standard Kennedy halves contain zero silver.
Most dates trade at or near melt, sometimes below. The 1970-D has lower mintage. These are considered undervalued by many stackers.