The Ja-Ru Spud Shot is a small potato gun (as the name implies) I got the Spud Shot as a stocking stuffer and didn't expect much of anything. That's good because I had to modify it to make it work at all.
At first I wasn't really sure how it could possibly shoot anything. Just from looking at it I could tell that the plunger had to be ridiculously small, and putting a finger over the barrel I could feel no seal whatsoever.
I decided to give it the benefit of the doubt and stuck it in a potato and tried to shoot it. Unsurprisingly, nothing happened. I tried different techniques of shooting. I squeezed harder and faster. I tried to squeeze and let go. For better or worse, it exploded into pieces.
This did give me an opportunity to examine the internals. As predicted, the plunger is miniscule. However, I looked at the plunger head and realized something must be wrong. I looked down the barrel and saw the plunger head, seal and all broken off inside the barrel. I extracted it and saw the rubber head that formed the seal was held on by a little piece of plastic that broke off, releasing the head. Superglue might have fixed that, but it would still be fragile and would probably break off again.
Instead, I took a more creative route and decided to solve it in a different way. I sanded down the base of the plunger head until it was flush with the plunger rod and turned the plunger head around backward and squeezed it on. Good as new, or maybe better, given the "new" one didn't make it out of the factory in one piece.
With that, I reassembled it and took it out to test it. Well, it formed a seal but also stuck instead of sliding smoothly like it was supposed to. After about 30 tries I got it to fire maybe 10 times. Better than nothing at any rate. The shots that did work made a nice crisp pop and flew somewhere around 20 feet. If it weren't broken it could be kind of fun.