Johnny Seven OMA (One Man Army) is a multi-function toy gun weapon produced by Deluxe Reading under their Topper Toys toyline, and released in 1964. Johnny Seven Gun O.M.A. was the best selling boys' toy of 1964, and was marketed heavily on children's television. It has a unique number of features, including seven different actions (hence the "Seven" in the name).
The "Johnny Seven" box came in two variations, one a standard box showing a boy looking through the sights of the toy gun, and the second (rare to find) showed a "Battle field" scenario behind the mounted toy gun with a see through plastic lid. The Johnny Seven gun was manufactured in four countries, and in order of rarity for collectors purposes, they were Australia, the United Kingdom, Canada (in a two language box) and the US version.
This toy gun is no longer made and has become a collector's item.
What's it worth? Take a look at this Johnny Seven Oma price guide: sold listings for a value indication.