Is This 1979 Kennedy Half Dollar Silver Weight Is 11.5 Grams?

@hth, see below for an old reply to a similar question from @conder101 over on another coin forum:


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1965 weight 12.5g 90% silver and 10% copper, 1965-1970 weight 11.5g 40% silver and 60% copper and nickel. 1971-present 11.34g composition 75% copper and 25% nickel (Copper nickel clad without silver). Half dollars have a Weight Tolerance of 4 grains OR +/- .26g so 11.34+.26=11.60 so its within tolerance if that tolerance information is accurate and still a normal non error copper nickel clad half dollar. This is the most likely answer since the composition should not include silver for that year and probably not worth investigating further unless its a year where silver has been part of the composition or known to be found in error.

You would also have to answer where a 40% silver clad planchet would come from at the Philadelphia mint. Philadelphia NEVER struck coins in the 40% silver composition. They stuck 90% silver dimes quarters and halves from 1964 to early 1966 and those were the last silver coins they stuck until the 90% silver Olympic commemorative dollars in 1983. And those early 90% silver coins were struck at a different mint location than the 1979 half dollar (Third Philadelphia mint, the fourth Philadelphia mint opened in 1969.)

The 1965 - 1969 40% silver half dollars carried no mintmark but NONE of them were struck in Philadelpia.