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High Performance Ammo

Post about things you have launched or thought about launching. Also post about various materials used for building cannons. No posts about explosive projectiles!
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High Performance Ammo

Unread postAuthor: sharpshooter » Thu Oct 24, 2013 8:37 pm

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 :shock: ). 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:
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Easy ammo.gif
Super quick ammo doodle
Easy ammo.gif (2.67 KiB) Viewed 926 times
Last edited by sharpshooter on Thu Oct 24, 2013 9:50 pm, edited 1 time in total.
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Re: High Performance Ammo

Unread postAuthor: Fnord » Thu Oct 24, 2013 9:22 pm

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.
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Re: High Performance Ammo

Unread postAuthor: sharpshooter » Thu Oct 24, 2013 9:33 pm

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

Unread postAuthor: Fnord » Thu Oct 24, 2013 9:39 pm

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.
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Re: High Performance Ammo

Unread postAuthor: sharpshooter » Thu Oct 24, 2013 9:52 pm

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

Unread postAuthor: jackssmirkingrevenge » Fri Oct 25, 2013 4:08 am

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

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

Have a look here: spud-cannon-related/topic22514.html?hilit=projectile%20testing%20any%20volunteers#p313591

Is GGDT still around?


These days we even have HGDT!

http://www.thehalls-in-bfe.com/HGDT/
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Re: High Performance Ammo

Unread postAuthor: sharpshooter » Fri Oct 25, 2013 1:20 pm

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.
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Re: High Performance Ammo

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Re: High Performance Ammo

Unread postAuthor: sharpshooter » Tue Oct 29, 2013 12:01 am

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?
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Simple Sabot Dart.png
Basic Sabot Setup
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Re: High Performance Ammo

Unread postAuthor: jackssmirkingrevenge » Tue Oct 29, 2013 7:10 am

A foam sabot will shred in the barrel.

Trust me :)



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 ;)
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