Goofy Weight Kennedy

The scale is accurate as I have weighed other coin denominations and they all weigh within .10 of correct.

Due to mint tolerances, weight is not a always a good way to tell the 40% silver from the clad. A 40% silver half can weigh as low as 11.1 grams (11.5 +/- .4 grams) and a CuNi clad half can weigh as much as 11.79 grams (11.34 +/- .45 grams)

A better test would probably be the tissue paper test, especially if you have known 40% and CuNi clad proof halves to use as controls.

Put the four coins in a diamond pattern with the two 76's at the top and bottom, the known 40% oat 9:00 and the known clad proof at 3:00. Place a single layer of tissue paper over the coins. (This can be done with the coins in 2X2's but it works better if the background around the coins is dark. You might place unused 2X2's, dark side up, over the 2X2's they are in.) The 40% silver proof will appear much whiter than the CuNi proof. Now just compare the color of your unknown proofs to the two known pieces.

This works because silver is the most reflective of all metals reflecting over 95% of all the light that hits it. The coppernickel only reflects about 70%. This difference is hard to see with the coins uncovered but the scattering of the light through the tissue paper makes it much more noticable.