Bizarre Cupr0-Nickel Penny

[Peckris 579]

These 'clacking pennies'. Do you mean coins with a laminating flan? If so, these were quite common amongst the decimal patterns of the late 1850's when they were experimenting with metals other than copper. The problem has been ascribed to using excessive pressure when struck, though this should presumably also apply in 1920 and I haven't seen any signs of this effect on early .500 silver unless they were typically struck with too little pressure which often appears to be the case.

Um, lami what? My penny just clacks when you drop it on a table, instead of ringing. Otherwise it looks perfectly normal.