I know that it's been used to take down masts. But since no one have mentioned it, i though i could do, and i cant think of anything more destructive.

Something destructive would be 2 steel balls with chain linking them together, i can imagine that would tear a large hole in something.

You can get a diesel injector test ting, it is very simple, just pull down a handle, and it generates enormous pressure, and releases it thru the injector, it is not so big, so it should be an easy task.

Dropping in when its pressured of only 100psi wouldn't do anything. 100 psi is not much, think of the compressor tank, i bet that its i MUCH thiner walls than your pipe, and they can hold a lot of pressure. I bet even a soda can could hold that pressure.

Some golf balls have to be pushed down, but most slide very slowly down (have to blow them down), so their size vary, but not much. I ordered the pipe on a factory where they build oil rigs (in Norway),i had to buy 5 meter for about 90$. The pipe is named: 50x3,5mm EN AW 6082-T6 Aluminum Pipe, the n...

I bought an aluminum pipe that is 50 mm outer diameter with 3,5 mm walls, 43mm inner diameter. Golfballs fits perfect, when the ball is on place, i can hold it in any angle, without the golfball falling out.

I always think "bigger have to be better" :P So on my combustion i have a chamber that is 9 Liter (550 Cubic Inch), and a barrel that is 4 Liter (245 Cubic Inch), and that is realy powerfull, shots golfballs over 350 Meters. I have bought steel pipe the same size now, and i'm gonna make a 8-9 Liter ...

You could make a system that locks the piston when it goes back, then the flow of gas would be maximum. Make it spring loaded, and something that locks/catches the piston in the back position.

I once shot a golf ball at a wall, that ball bounced back and hit my cussin in the ass, lucky for me it was a bad mix of fuel/air. But it still hurt like hell he said.
Normally, the balls went thru the wall, but when the mix and angle of the shot was wrong, the ball came back.

yes, it ABS. I'm not completly finished with it yet, still need a few modifications.

I'm posting a link to some photos of my cannon.

http://forums.spudtech.com/topic.asp?TOPIC_ID=9545

Yes, its very tight, the are made 1mm to big, så i have to hammer it down.

Today i managed to shock myselfe with the coil, and i cant recomend it to anyone!! It hurt like hell!

I got it to work now :D didnt have to add any wires except the wires to the coil. I'v found out that if i have a button for the batery, so i can turn it on/off, and a button to the + pole on the coil, its much more easy. Just turn the batery on, wait a few seconds, and then turn the switch to the co...

I'f you add a coil to it, you can transform it up to 100,000 Volts (depending of the coil)