I bought a partial tube of Targeteer BB's on ebay; this one is also for sale. Advertised as a full tube but to me these look like full size BB's or maybe shotgun pellets. I asked the seller; he doesn't know and doesn't have a way to measure them. So, opinions? Since I already have a tube coming I don't need another and don't need the BB's if I can't shoot them.

https://i.imgur.com/FjsuJHhl.jpg

Phil, maybe even farther from a double, but Lefever related. There may have two or more designs. I seem to remember one was called a Liquid Gun , and this one is the Daisy No. 71 Water Pistol.

https://i.imgur.com/5BzAshc.jpg

Phil possibly 5 1/2 shot would be closest.

Daryls posting of the gun above reminded me of a pistol we had as a kid called a Spud gun.
I found a picture of an example on the web.

Phil, did it shoot a raw potato loading ?

You pushed the end of the barrel into a raw potatoes, and then turn the gun to the side breaking off a piece of potato. Pulling the trigger shot the piece of potato about the size of a 22 caliber out the end of the barrel.

It's all coming back to me, now. Thanks