Johnny
Reb 
I receive many requests for information about "a cannon" that was played with by "my husband" when he was a child. Do you know what it was?
In all probability it was the "Johnny Reb" cannon.
This cannon was introduced in 1961 and made by Remco. It would shoot plastic balls 35 feet by a spring loaded, lanyard fired mechanism. It came with balls, a plunger and a Confederate flag.
It was one of those "great toys" that usually ended up confiscated. You can still find these in tag sales, however they probably sell for more than $ 8.00.
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