My ammo
- stuffbuilder
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Just made some new ammo for my 2.5" air cannon: 90 calorie soda cans filled with concrete! They fit pretty good and certainly have some weight to them. Thoughts?
- stuffbuilder
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I will be shooting them with a piston valve gun, but unfortunately that gun doesn't work right now due to a bad piston seal (its a chamber-sealing valve). Given that college dorms don't allow potato guns, it will probably be awhile before the gun can be fixed.
And I had been planning on using regular cans, but they're just a bit bigger than a 2.5" barrel
And I had been planning on using regular cans, but they're just a bit bigger than a 2.5" barrel
- velocity3x
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My guess is that the projectile weighs about 590 grams. Unless your cannon is metal construction using high pressure, I wouldn't expect much other than heavy recoil and broken parts. Hope it works for you.stuffbuilder wrote:90 calorie soda cans filled with concrete! Thoughts?
- stuffbuilder
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Its all schedule 40 PVC. If the cans are too heavy the barrel will probably just pop off the elbow coming from the valve (it isn't glued). And there is space around the cans that air can leak through
- Moonbogg
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I don't get why piston housings break from heavy projectiles. Shouldn't the housing be able to withstand the full potential of the piston and chamber pressure? I mean, you should be able to plug the barrel, vent the pilot and the housing shouldn't break. At least that makes sense to me, I don't know.
Anyways, id love to see your ammo fly. I might be shooting some soda cans in the near future myself.
Anyways, id love to see your ammo fly. I might be shooting some soda cans in the near future myself.
I would like to do it, but dont wanna damage my piston or housing
I will be shooting them with a piston valve gun, but unfortunately that gun doesn't work right now due to a bad piston seal (its a chamber-sealing valve). Given that college dorms don't allow potato guns, it will probably be awhile before the gun can be fixed.
And I had been planning on using regular cans, but they're just a bit bigger than a 2.5" barrel
why are you worried about ammo ,if you cant shoot it anyways?
I will be shooting them with a piston valve gun, but unfortunately that gun doesn't work right now due to a bad piston seal (its a chamber-sealing valve). Given that college dorms don't allow potato guns, it will probably be awhile before the gun can be fixed.
And I had been planning on using regular cans, but they're just a bit bigger than a 2.5" barrel
why are you worried about ammo ,if you cant shoot it anyways?
Moonbogg, the issue with piston housings breaking isn't caused by internal pressure, but by dynamic loading on the housing from the recoil. This is, of course, particularly hard on tee valves. If the barrel was more securely fastened than we tend to bother with, it wouldn't be so much of a problem.
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DYI wrote:Moonbogg, the issue with piston housings breaking isn't caused by internal pressure, but by dynamic loading on the housing from the recoil. This is, of course, particularly hard on tee valves. If the barrel was more securely fastened than we tend to bother with, it wouldn't be so much of a problem.
so is it dangerous to shoot soda cans filled with concrete then?
- Moonbogg
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Oh I got it now. I thought it was from the piston's kinetic energy when exposed to the full pressure of the chamber while using a heavy projectile. The recoil thing makes perfect sense of course. Like you said, it would be better to take some load off of the housing's joint with the chamber for heavier projectiles.DYI wrote:Moonbogg, the issue with piston housings breaking isn't caused by internal pressure, but by dynamic loading on the housing from the recoil. This is, of course, particularly hard on tee valves. If the barrel was more securely fastened than we tend to bother with, it wouldn't be so much of a problem.
EDIT: For a PVC cannon in an over under design I would say it may be unwise to shoot soda cans filled with concrete, yes.
Moonbogg wrote:Oh I got it now. I thought it was from the piston's kinetic energy when exposed to the full pressure of the chamber while using a heavy projectile. The recoil thing makes perfect sense of course. Like you said, it would be better to take some load off of the housing's joint with the chamber for heavier projectiles.DYI wrote:Moonbogg, the issue with piston housings breaking isn't caused by internal pressure, but by dynamic loading on the housing from the recoil. This is, of course, particularly hard on tee valves. If the barrel was more securely fastened than we tend to bother with, it wouldn't be so much of a problem.
EDIT: For a PVC cannon in an over under design I would say it may be unwise to shoot soda cans filled with concrete, yes.
more less dont shoot cans filled with concrete then!!!
- stuffbuilder
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I'll have to keep that in mind. Right now all the recoil would just go through the elbow and into the valve, but I can probably secure the barrel to the gun frame somehow to avoid that.the issue with piston housings breaking isn't caused by internal pressure, but by dynamic loading on the housing from the recoil
- mattyzip77
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start off using filled tennis balls, use sand or whatever to fill themand see how that works first. A soda can filled with concrete seems way too heavy to me. Something is bound to break, and hopefully its not your skull!!!
Go Bruins!!!!
- stuffbuilder
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At first I was going to use sand, but there was some leftover concrete from a home improvement project that we needed to get rid of, so I used that instead. But to be completely honest, the gun has never fired. I had finished putting the piston in, but when I went to fill it up with air, it all leaked out through crappy O-ring grooves. School started before I could fix it.