Thanks for your help guys.

That link was really helpful. A ball valve on a stick--both simple and elegant. I should be able to adapt it to my purpose and avoid the complication (and cost) of electronics.

As for the loading mechanism, I was not asking anyone to spoon feed me a diagram with ...

So I have been thinking about how to make a Pump Action AA battery gun and after searching the forums I have a few questions. I have a sort of preliminary design (see illustration below). I am still working out the actual pump loading mechanism, but I am sure that if I think about it long enough, I ...

And NOW you tell us that?

Ok, so I didn't realize that my grandfather had one in his shop until I was talking to my dad about it and he mentioned it. It will make things a lot easier when I can get down to use it. Anyway I will find some suitable material and make a properly sized piston that I ...

Ok, so last night I both retaped the piston and shrunk the pilot volume as psycix suggested. I got the gun working again and think it is now more powerful than before, but that is just my observation, since I have no true way to compare it. This weekend I am going to work on a more permanent piston ...

Thanks so much Mark. You were right and your electrical tape solution worked perfectly for about 10 shots until the tape started to come off (that's all I could ask it to work I guess). And what a 10 shots they were!! That thing is powerful! Somehow I cracked a golf ball. :shock:

One question ...

I have been trying my hand at a piston valve for a few weeks now and when I finally went to try it out, all I got was the unsatisfying hiss of all the air leaving the pilot. When I opened up the chamber, the piston had not moved AT ALL. I tried it a few more times and still, nothing. I have been ...