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Odd but effective alternate ammo

Unread postPosted: Mon Nov 20, 2017 11:03 am
Author: Cthulhu
I'm sure we've all used some pretty weird things shoved into a Spud gun barrel to shoot, but have you ever used something so strange yet it actually has good performance?

I recently built a cheap-o sprinkler valve mortar with 2" PVC and I was amazed that empty caulk tubes could fly up to 500 feet!

Re: Odd but effective alternate ammo

Unread postPosted: Mon Nov 20, 2017 11:35 am
Author: jackssmirkingrevenge
Careful what you point it at, you don't want to call 911 to say someone has been injured by a flying caulk :D

Re: Odd but effective alternate ammo

Unread postPosted: Mon Nov 20, 2017 11:44 am
Author: mrfoo
you don't want to call 911 to say someone has been injured by a flying caulk


Especially if your accent makes it come out as "flying cock".

Re: Odd but effective alternate ammo

Unread postPosted: Mon Nov 20, 2017 11:53 am
Author: jackssmirkingrevenge
mrfoo wrote:Especially if your accent makes it come out as "flying cock".


http://thatsthejoke.com

Re: Odd but effective alternate ammo

Unread postPosted: Mon Nov 20, 2017 2:39 pm
Author: Air2theBrain
500ft! :shock:

How much does that tube weigh..? :P

How much psi did you use? 8)

Re: Odd but effective alternate ammo

Unread postPosted: Mon Nov 20, 2017 5:38 pm
Author: Cthulhu
Air2theBrain wrote:500ft! :shock:

How much does that tube weigh..? :P

How much psi did you use? 8)


I haven't weighed the tube, but when I do I'll post it.
I'm running at only around 40 psi. The reason for the immense range is that since it's a mortar it's fired at 45°. When aimed horizontally it only goes about 45-50 feet.

I'll probably make a separate thread about it later, but I want to build the bipod and baseplate first.

Re: Odd but effective alternate ammo

Unread postPosted: Tue Nov 21, 2017 9:21 pm
Author: Cthulhu
The caulk tubes sadly break after hitting the ground so many times, so I've been trying to replicate their design, but I encountered some problems.

How do you calculate the optimal mass for a projectile to get the best range?

Is there a way I can get my projectile to whistle as it flies?

Re: Odd but effective alternate ammo

Unread postPosted: Wed Nov 22, 2017 5:03 am
Author: Air2theBrain
Found this link, looks heavy mathematical. :shock:
https://www.whitman.edu/Documents/Acade ... lsmith.pdf

Re: Odd but effective alternate ammo

Unread postPosted: Wed Nov 22, 2017 6:02 am
Author: jackssmirkingrevenge
Cthulhu wrote:How do you calculate the optimal mass for a projectile to get the best range?


GGDT includes an External Ballistics Tool that can be helpful.

Is there a way I can get my projectile to whistle as it flies?


Stick one of these on the front ;)

Image

Re: Odd but effective alternate ammo

Unread postPosted: Wed Nov 22, 2017 6:29 am
Author: Air2theBrain
Jack i was thinking of these when i read this post also. :)

For something funny i would throw an actual whistle in the tube.

You wanted it to whistle right? :P

I heard of a guy putting a whistle in his blow off valve for his car...would have made people turn their heads thinking a referee was on the streets.

Re: Odd but effective alternate ammo

Unread postPosted: Wed Nov 22, 2017 6:51 am
Author: jackssmirkingrevenge
I heard of a guy putting a whistle in his blow off valve for his car...would have made people turn their heads thinking a referee was on the streets.


Antonios, Mentale!!! :D

hehehe been a while since the last Chanel 9 Neus reference on this forum, @POLAND_SPUD where you at?

Re: Odd but effective alternate ammo

Unread postPosted: Wed Nov 22, 2017 11:57 am
Author: Cthulhu
Air2theBrain wrote:Found this link, looks heavy mathematical. :shock:
https://www.whitman.edu/Documents/Acade ... lsmith.pdf


That's mostly about optimal launch angle rather than optimal mass, funnily enough I've actually seen that exact article in my physics class a couple years ago to show the proof behind the whole "45°" launch angle belief.

Found a way to get it to whistle without having to buy a nerf football: I cut the head off a nerf mega dart (which have whistles built in) and glued it to the head of my projectile.


Mass is still a problem.

Re: Odd but effective alternate ammo

Unread postPosted: Wed Nov 22, 2017 12:23 pm
Author: jackssmirkingrevenge
Mass is still a problem.


Pour some cheap epoxy into the head ;) I would really suggest you play with GGDT to figure out the optimal weight for the parameters you are using.

That's mostly about optimal launch angle rather than optimal mass, funnily enough I've actually seen that exact article in my physics class a couple years ago to show the proof behind the whole "45°" launch angle belief.


For a drag stabilized projectile it's usually closer to 55 degrees.

Fr Frog has some relevant data on the Fin Stabilized M829 anti-tank round.

Re: Odd but effective alternate ammo

Unread postPosted: Wed Nov 22, 2017 4:53 pm
Author: Cthulhu
I dumped a bunch it bits of scrap metal into the body and sealed it with hotglue under a foam disk. It exploded as it left the barrel, but it's a start!
I put an ad out on Craigslist saying I was buying used caulk tubes, let's see if I get any bites!

Re: Odd but effective alternate ammo

Unread postPosted: Wed Nov 22, 2017 4:56 pm
Author: jackssmirkingrevenge
Cthulhu wrote:I put an ad out on Craigslist saying I was buying used caulk tubes, let's see if I get any bites!


"Hi, heard you were paying for used caulk?"

"Uhh..."