SpudFiles

Howdy folks, Its been years since I've done anything cannon related, but the bug has bitten again. (I left shortly after the SpudTech forums closed ). Good to see folks still hard at it.

I now have occasional access to the machine shop at work, and have been playing with micro-controllers lately. One day it hit me: Select fire Hybrid. To make this worth while, i need some slick ammo. I shot a few machined aluminum/steel darts out of my 500ci combustion the other day with fantastic results (sorry, no damage pics) but they take far to long to make.

Here are my requirements:
-Be able to make dozens in an hour (excluding dry time)
-Work for 10-20mm (3/8"-3/4") barrel
-prefer ammo to be stackable so I dont have to use shells/sabots
-Cost under $1 per shot in materials (including sabot etc)
-Does not require a lathe, mill, or welding (soldering or some easy heat fusing is ok)
-I dont mind casting lead, but the shipping cost adds up quickly (no local source)
-design is adjustable to different weights

My idea right now is to use thin walled aluminum tubing with a steel lug at the end, like my attached image.

I am not sure on weight right now, as I am in the very early design stage. Is GGDT still around? I might have it archived on an old harddrive around here some where....
Any ideas are appreciated :bom:

Might want to crimp that tubing on there rather than epoxying it. Hitting a hard surface at high speed is gonna put the joint under quite a few thousand g's of shearing force.

Good call. Do you think the acceleration in the barrel will blow the steel out? Or are you thinking once it hits the target?

Think about it. You take a mass and accelerate it to, say, 500fps over one meter. Then you suddenly decelerate it to 0 fps over one centimeter. The shock of impact is easily greater by orders of magnitude.

Agreed. But leaving the tube behind on impact is relatively unimportant, as long as it sticks on to stabilize during flight.

This new layout seems to be bringing veterans out of the woodwork

Either that or former teenagers are now adults who need a distraction from the wife and kids

Have a look here: http://www.spudfiles.com/spud-cannon-re ... rs#p313591

Is GGDT still around?

These days we even have HGDT!

http://www.thehalls-in-bfe.com/HGDT/

Brilliant, FMJ! Great minds and all that. Have yet to read it all, but it looks like you've done all the legwork for me.

I'm excited to try HGDT. Hopefully I can get it to work in Ubuntu/wine.

Who else has come back? I fall in the former teenager category. Looking back, I can't believe all the stuff I built without the proper tools/funds.

It looks like there is no denying the power and efficiency of a sabotted dart, which will also require the use of a shell. Which means I can't get too exotic with barrel choice, or my shell cost will go through the roof.
I am thinking some sort of polyethylene cylinder purchased in the appropriate size so I just need to bore a hole in the center and slit it in half, as shown in the provided doodle.

Also, the forming of the aluminum pipe into tail fins using a 3 or 4 jaw chuck is simple yet effective- Perfect.

Any thoughts on sabot material/production?

A foam sabot will shred in the barrel.

Trust me

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If you're making a hybrid, I don't think saboting your rounds is really necessary. Unless you're really fixated on penetrating thick steel plates, a full bore slug from a hybrid will go through most discarded domestic appliances spudders typically shoot at