was there a shortage of coin?
Yes.
Coinage Act of 1965
There had been coin shortages beginning in 1959, and the United States Bureau of the Mint expanded production to try to meet demand. 
when was silver taken out of us coins 1965 when was this act enacted? July 23, 1965
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Coinage Act of 1965 [SEP] Introduction
The Coinage Act of 1965, , eliminated silver from the circulating United States dime (ten-cent piece) and quarter dollar coins. It also reduced the silver content of the half dollar from 90 percent to 40 percent; silver in the half dollar was subsequently eliminated by a 1970 law. There had been coin shortages beginning in 1959, and the United States Bureau of the Mint expanded production to try to meet demand. The early 1960s was a time of increased use of silver both in the coinage and in industry, putting pressure on the price of silver, which was capped at just over $1.29 per ounce by government sales at that price.