Harris Marksman Air Pistol.
The first version of this ubiquitous low-powered design. With thanks to John G for the pic.
He says:
Nothing much unusual about this you may say, as the Marksman repeaters have been made in their hundreds of thousands over more than half a century and you can pick them up anywhere. However, if you look closely at this one, you will see that there is no mention on the box lid that the gun is a repeater. It is in fact an example of the rare single shot model, which was only on the market for 2-3 years. Even more unusual is that the grip has a patchbox, with two separate compartments for pellets and BB’s. for holding pellets. This feature, easily overlooked, was only available with the very first guns introduced in 1955, and was only available for a year, disappearing by 1956. I picked this gun up for next to nothing some years ago, as its rarity was not appreciated by the dealer.
With thanks to Stu of MrGuns Place for permission to post this pic of a slightly later pistol.
Boxed Harris Marksman Air Pistol