Spudgun power

Boom! The classic potato gun harnesses the combustion of flammable vapor. Show us your combustion spud gun and discuss fuels, ratios, safety, ignition systems, tools, and more.

More or less then 4.2lbs /square inch???

more (i hope not:( ).
5
83%
less ( i hope ).
1
17%
 
Total votes: 6
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Demon
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Fri Mar 06, 2009 6:44 pm

In the Canada, whats cool is that combustion and pneumatic weapons are considered as the same BUT the fps must not be higer then 500 and the energy of the projectile more then 4.2 lbs/per square inch.

Do you think that a normal combustion spudgun can reach 4.2 lbs/inch 2 ?

Mine is 2" per 18" chamber and 1.5 " per 36 " barrel.
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sgort87
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Fri Mar 06, 2009 8:17 pm

The standard combustion launcher hits an average of about 40 PSI through the entire shot. That's a bit more than your 4.2. You're pretty screwed.

A 4.2 PSI shot will plop a spud a couple feet from the barrel. It's pretty unimpressive. :P
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Combustion Monkey
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Fri Mar 06, 2009 8:28 pm

According to HGDT my golf ball combustion is generating around 80 psi chamber pressure and 625 ftlbs of muzzle energy a bit past what your laws may tolerate. Thats just a 1x combustion. Is your law regulating chamber pressure or force generated by the projectile?
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MrCrowley
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Fri Mar 06, 2009 10:19 pm

sgort87 wrote:The standard combustion launcher hits an average of about 40 PSI through the entire shot. That's a bit more than your 4.2. You're pretty screwed.

A 4.2 PSI shot will plop a spud a couple feet from the barrel. It's pretty unimpressive. :P
He's talking about projectile energy, not pressure. :)
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TwitchTheAussie
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Fri Mar 06, 2009 10:44 pm

Combustions have a load of different psi peaks depending on several factors. I'd say your pretty safe mate. Just stay safe and remember not to aggrovate the piggies and you'll be right :P
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sgort87
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Fri Mar 06, 2009 10:48 pm

MrCrowley wrote:He's talking about projectile energy, not pressure. :)
Ohhhhhhhhh.......... Yeah, that's a lil different.
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Ragnarok
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Fri Mar 06, 2009 10:50 pm

MrCrowley wrote:He's talking about projectile energy, not pressure. :)
What he means, is not pounds per square inch, but ft-lbf, or foot pound force... or generally foot pounds in short, with the force omitted.

In answer, yes, almost all spudguns exceed 4.2 ft-lbs. Only the small minis and airsoft guns are likely to be incapable of reaching that mark.

My understanding of Canadian law was that to require registration, the launcher/firearm/etc had to be capable of exceeding both 500 fps and 4.2 ft-lbs. However, I must state that although I'm quite knowledgeable about the firearms law in my own country, I don't normally bother studying that of other countries in much detail, so I may well be wrong.

Whether it's an AND or an OR situation is important, and I can never remember which - I think I've heard both quoted, and I believe it's AND, but really... don't hold me to that, check.

Whichever way it is, as my air rifle is about ~800 fps and ~11 ft-lbs, it doesn't need registration in the UK, but would in Canada.
And if a firearm is legal in the UK (in the UK, air rifles are considered firearms under legal terminology), but not elsewhere, that tells you something about how tight the elsewhere has to be.

Alternatively, with regards to law, you can use the LOTISC in any country if questioned by a police officer, but don't rely on it, it's best used with the 11th Law.
Personally, I use the 11th law and LOTISC - with a backup of legal loopholes and definitions for if I am genuinely challenged.
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Hotwired
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Fri Mar 06, 2009 11:44 pm

Ragnarok wrote:Alternatively, with regards to law, you can use the LOTISC in any country if questioned by a police officer, but don't rely on it, it's best used with the 11th Law.
Personally, I use the 11th law and LOTISC - with a backup of legal loopholes and definitions for if I am genuinely challenged.
I'd pay good money to see you try that out :P
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daccel
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Sat Mar 07, 2009 2:52 am

It must exceed both to be considered a firearm under the Firearms Act and require registration. However, if it exceeds either then it is considered a firearm under the Criminal Code (ie. if used in a crime).

If you're concerned, run your specs in HGDT and find out where you stand.

Unless you're planning on using it in public, or knocking off a bank with it, I wouldn't be too worried.
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Demon
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Sat Mar 07, 2009 8:41 am

I,ve made the maths, and the 40 grams potato i use must go to ....
......15m/sec to be legal.......

Man! i can throw it way faster then that! it even does'nt beats a mini airsoft....

I've send a e-mail to the cfac ( canada weapons agency ) on using potato's as projectiles and we will see.

(My dad, even if he is very strict on the law, was saying c'mon, potatos dont counts, they cant be dangerous)

In canada, you can build a 600 psi gun if it is for an strict usage, like throwing ropes to climb, so i will put a lot of warning messages on it like "only use potato's" and myself, never shoot any other thing then fruits.
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Ragnarok
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Sat Mar 07, 2009 9:13 am

Hotwired wrote:I'd pay good money to see you try that out :P
Well, that's what I'm already doing. The first level of defence is not getting caught - the 11th law.

I haven't yet been called upon for the LOTISC, but it might work in the right circumstances, especially if done in the right way. Admittedly, it's not a step in the chain that should be relied on, but I'm not discounting it on that basis.

Loopholes - anything in the UK that's used as a paintball gun is considered outside the scope of the firearms acts, with no notes on limiting power. Most of my launchers can pass as paintball guns, so I can push that point.

Finally, worst case scenario, nothing else working, under UK law, nothing I have is actually illegal - at worst, it's unlicensed, which carries much lesser sentencing.
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psycix
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Sat Mar 07, 2009 11:23 am

Ragnarok, what do you mean by LOTISC?
Google can't clear things up for me.
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Ragnarok
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Sat Mar 07, 2009 1:16 pm

psycix wrote:Ragnarok, what do you mean by LOTISC?
Law Of "That Is So Cool" - in other words, hoping that whichever officers you're talking to focus on the awesomeness of your cannon rather than it's legal status.
Does that thing kinda look like a big cat to you?
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Sat Mar 07, 2009 1:37 pm

Demon wrote:
(My dad, even if he is very strict on the law, was saying c'mon, potatos dont counts, they cant be dangerous)
Oh, they can be very dangerous coming from a potato cannon.
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Ragnarok
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Sat Mar 07, 2009 10:32 pm

TurboSuper wrote:Oh, they can be very dangerous coming from a potato cannon.
They certainly can be. However, put almost anything to a few hundred feet per second and it runs the risk of damaging, injuring or killing something.

What might seem safe at 30 fps becomes far more hazardous at 300, because things work differently at those speeds. Indeed, at launcher speeds, even vegetable matter will act much more solid and hard than it is normally.
Does that thing kinda look like a big cat to you?
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