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Posted: Fri Jun 19, 2009 6:09 pm
by noob of noobs
I'd second the DDT theory.
So does figure 6.7 in the link. http://www.spudfiles.com/forums/first-h ... 18493.html

If you plan on continuing to use such a long barrel on such high mixes, maybe a copper barrel would actually be a better option? If copper bursts under detonation, it's more maleable and will probably just blow off, but if steel breaks, there's more schrapnel. Or perhaps surround the copper barrel in steel as a kind of shield?

By the way, the flattened round is awesome!

Posted: Sun Jul 05, 2009 6:59 am
by vince
Update:

Shot at a 4mm thick Steel Plate at 20x and it went through without problems.
I tried to do it again (at 20x) to see if I can get through 6mm Steel and my barrel exploded :shock:

Posted: Sun Jul 05, 2009 7:52 am
by MRR
WOW :shock:
I guess that was loud. Hope you didn't get hurt.


Did you check the proper fit of the projectile (pushed it trough the barrel) before you fired?

I had my copper/brass gun in my trunk and after that only 1/3 of my ammo (marbles) were able to pass. I had to buy a new barrel because of a tiny dent.

Posted: Sun Jul 05, 2009 8:36 am
by starman
That's some serious penetration there my man... :shock: Looks like the copper failed fairly "safely" if there is such a thing. Obviously, the copper wasn't up to 20x shock and stress requirements.

Any idea what the psi burst point of the disk was?

Posted: Wed Jul 15, 2009 5:43 pm
by SpudFarm
inspiration in the class of gods!

i guess i will have to build another hybrid now.

i can certainly place my money (and more that can't be mentioned (A) ) that you got two DDT's, i don't think just a small portion of the barrel would fail otherwise. atleast it should only make a tear i think.

good work my friend!

Posted: Wed Jul 15, 2009 8:17 pm
by MrCrowley
Haha celebrating when something goes wrong...only at Spudfiles :wink:

Nice build, I feel sorry for your neighbours. Where abouts in Germany are you?

Posted: Wed Jul 15, 2009 8:57 pm
by FORE!!!!
lmao whats on the other side of that timber fence,,,,nothing i hope!!!

and what size is the wall thickness on that copper tube,,in australia we have type a-d ( a )being the thickest wall

Posted: Thu Jul 16, 2009 1:04 am
by Moonbogg
The round bulge before the break looks just like your previous experience. That sure is a convinving case for DDT having happened twice to you.

Posted: Thu Jul 16, 2009 1:57 am
by jackssmirkingrevenge
MrCrowley wrote:Haha celebrating when something goes wrong...only at Spudfiles :wink:
It never goes "wrong" - the primal objective ingrained in our psyche is always perforation, whether it's of the target or the barrel, a result is a result :D

Fantastic work vince :) though I'm guessing at these pressures you shouldn't be working with copper...

Posted: Thu Jul 16, 2009 2:22 am
by MrCrowley
jackssmirkingrevenge wrote:
MrCrowley wrote:Haha celebrating when something goes wrong...only at Spudfiles :wink:
When disaster strikes, we rejoice (assuming none of us are hurt) :)

Posted: Thu Jul 16, 2009 11:15 am
by vince
Hello,

I've been busy with another Cannon and I still don't have a Steel Barrel.
Also my neighbors told me that they will call the police if I shoot "that thing" again.
So I guess I will have to shoot in my basement from now on.

@starman
I used a burstdisk made of 0,3mm aluminum sheet. No idea what the burst pressure was.
@MRR
Yes I pushed it through the barrel without any problems. I was standing 3 meters away and behind a brick wall so there was zero chance I would get hurt.
@MrCrowley
I live in Duisburg - North Rhine-Westphalia.
@FORE!!!!
The wall thickness of the copper is 1mm. There is a concrete wall behind the fence so don't worry :wink:


This is my new "Cannon". Its just a huge Combustion Gun without a Barrel.
I use 2-3 sheets of Paper as a burst disk and then about 1 pound of flour on top of that.
In the video it was Spray and Pray but now I got a Propane Meter + Chamber fan.
Will be nice for New Year's Eve :)
[youtube][/youtube]

Posted: Thu Jul 16, 2009 7:42 pm
by rna_duelers
So your going from using your pipe bomb gun outside to inside a small enclosed room for firing....I like it!Any possibility of video?I'd love to see one of these failures on video,if you could induce one again.

Very nice gun and that flattened lead round.Priceless,looks awesome.

Posted: Fri Jul 17, 2009 12:16 am
by jackssmirkingrevenge
vince wrote:Also my neighbors told me that they will call the police if I shoot "that thing" again.
Always a sign of spudding success :) it pays to be a bit more cautious though ;)

Posted: Fri Jul 17, 2009 10:11 am
by vince
So your going from using your pipe bomb gun outside to inside a small enclosed room for firing....I like it!Any possibility of video?I'd love to see one of these failures on video,if you could induce one again.

Here you go. Sorry it didn't blow up again :P

The Projectile made it through 7,5mm Steel and still had enough Energy to destroy the Stone behind it.
Check out the recoil :shock:
[youtube][/youtube]

Posted: Fri Jul 17, 2009 10:21 am
by starman
All that indoor shootin' makes me cringe a little. Hopefully you weren't in the same room at the time.

However, the C-beam penetration is very impressive indeed!!