Im making black powder shell shotgun with 3/4 inch pipe, how

googled black powder pressure calculator

http://www.huntingnet.com/forum/black-powder/95534-black-powder-pressures-velocity-chart.html

also 10 bar is 145 psi, so, lol

I don't mean to be critical, but if you need to ask the internet if the device you want build can withstand an internal explosion....

>>33024865
he should microwave it for safety.

Don't people just use seamless black pipe?

I am a pipefitter/welder. You are going to die if you use that.

It's important to test it first. Fill the pipe with blackpowder and cap it off at both ends. Stand at least 3-4 feet away for safety reasons when you set it off.

If you don't see any cracks during the test firing then it'll be fine to shoot out of.

Between this thing blowing up and the ATF, your doggos are toast.

>>33027473
This.

BTW pipe welders make some fun shooty objects. My welderbro made a sweet bowling ball cannon out of an old nitrogen cylinder I gave him.

OP better proof test that turd with a long string. I strongly recommend sand bags for cover.

speaking of making funs, since i don't want to make a new thread entirely:

I haven't been on /k/ in a while, did anything happen with that guy who was saying he could make a super cheap rifle with a brand new design nobody had ever tried before?

it had some dumb meme-y name which I think included pepe

>>33027494
This

>>33024492
Me and my brother made a pipe cannon with a 36" barrel out of 1" 150psi pipe. We loaded it with 200 grains of FF black powder with 8 .454 round balls as shot and it worked just fine. We didn't proof test the thing, but it has lasted for 10 shots just fine. We certainly didn't try holding it while it went off though.

>>33028904
still waiting on it, i'm not hopeful

>>33030880
>it has lasted for 10 shots just fine
as in you only fired it 10 times, or did it fail after 10 fires?

>>33024492
They use heat-treated hydraulic pipes to manufacture muzzleloaders. If they'll hold up to black powder, they should be fine for a modern day fowling piece.

>>33032169
Hasn't failed yet. No visible bulging, but again, we didn't measure with calipers. I'll upload a webm of it firing after I get done playing rivals with my buddy.

>>33033286
I can't figure out how to remove webm audio so whatever. Here it is on youtube instead:

https://www.youtube.com/watch?v=s3j4TB9JNY0&feature=youtu.be

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>>33033675
And as you can see, these were no light loads—the pipe was braced directly against the board each time. I wouldn't want to shoulder this thing.

>>33024492
How many grains of powder are in the shells you're going to use, op?

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>>33033734

jesus fuck

>dindu breaks into house
>point your literal fucking handcannon at him
>d-dont fucking mo-move
>he puts his hands up and complies
>please man i dont want to die im just trying to feed my family
>thats j-just what a synth would s-say
>here hold this
>hand him the ShoulderFucker9000
>he points it at you and pulls the trigger laughing
>room instantly fills with smoke
>fire department arrives
>smoke clears out
>dead redguard with half his skeleton coming out of his shoulder cavity
>firefighters see you standing there unscathed
>it was a chicken tendy +p+ handload
>wipe crumbs out of neckbeard
>tip fedora
>"nothing personnel kid"
>become range buddies with firefighters

fin

>>33034039
>ShoulderFucker9000
Had a hearty kek.

>>33028904
>>33031367
He finally fucked off and stopped shitting up the board with a thread per day along with a cad drawing of 2 pipes and a rectangle.

I hate it when threads like this are made and OP misses the content.

>>33034039
Kek
>ShoulderFucker9000
it is a good one

>>33024492
Start with seamless pipe as a minimum. Next, Strongly consider getting a machine shop to drill out some round stock for you.

1 inch diameter drilled from the center to 3/4ths an inch, leaving you with some good thick metal.

https://en.wikipedia.org/wiki/Gauge_(bore_diameter)#Sizes_in_use
https://www.amazon.com/Carbon-Unpolished-Finished-Standard-Tolerance/dp/B00CNM6Z8Y

Look up your metal. Dont tell the shop the tube is for a gun, and they wont care. Its not like it has rifling on it, so you arent doing anything illegal. Shit, you could even get both ends threaded for fun.

>>33027494
*sigh* that is a pipebomb anon, and it would kill OP. While its funny, i no longer assume anyone has common sense.

What pipe are all those slam bang shotguns made of? There are shit tons of videos of people shooting them safely and that royalnonesuch torture test video he did.

>>33037638
>Look up your metal. Dont tell the shop the tube is for a gun, and they wont care. Its not like it has rifling on it, so you arent doing anything illegal.

if you don't use an 18 inch barrel it's illegal

>>33024865
yep. stop building until you understand the physics

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>>33037758
>use 20 in barrel
>ATF rapes my dog and makes me watch
>"should've went two inches shorter, kid."
>shit on my car before they leave

>>33024492
>Tries to build shotgun out of pipe
OP is autistic confirmed.

>>33038744
But it works

>>33024492
use the following equation to calculate allowable pressure for any pipe:

(Sy / n) * ((R_outside^2 - R_inside^2) / sqrt(3 * R_outside^4 + R_inside^4)) / 10^6

Sy: Yield strength of material
n: Factor of Safety
R_outside: Outer pipe radius
R_inside: Inner pipe radius

And for fucks sake use unwelded seamless pipe.

Perhaps use some 1"OD x 3/4"ID for the barrel layered with 1.5"OD x 1" ID to reinforce the chamber and first ~6" of barrel.

https://www.onlinemetals.com/merchant.cfm?pid=7339&step=4&showunits=inches&id=250&top_cat=0

https://www.onlinemetals.com/merchant.cfm?pid=21050&step=4&showunits=inches&id=250&top_cat=0

Shit should allow for ~153 MPa of barrel pressure. 12ga shells are only ~132MPa Max proof pressure CIP, assuming a yield of 360 MPa. Should take note that 4130 endurance limit is ~340 MPa, but I doubt you'll be shooting this thing very often.

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>>33024865
BP doesn't explode, it burns, just saying

>>33038676
Under 18 is illegal, you twat waffle.

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>>33034039
merry christmas, get a cap

>>33024492
I don't know about your science man, becuase what system of measurement uses bar?

Anyways, when I made mine, I just figured as long as the pressure produced by the round was inferior to the burst pressure of the pipe, I would be good to go.

Ref.
http://www.engineeringtoolbox.com/stainless-steel-pipes-bursting-pressures-d_463.html

I made a thread, but I'd have to dig in the archive for it.

>>33042787
ref.
https://desuarchive.org/k/thread/29425905/#29426017

>>33040285
>unwelded seamless pipe.
Y'see, I keep seeing that warning, but if the welded pipe is verified to meets the same standard as unwelded, why should I care?

>>33042864

because "standard" might not mean "im going to cause 5000 explosions to happen right next to my face and see if i die in the process". I imagine it's more of a failsafe while pushing the upper limits.

but i literally know nothing so that's just my guess. i'd say if you keep seeing the same warning, trust it.

>>33042249
Thanks, mate.

>>33038676
If that thing is chambered in anything stronger than 9mm, that wire stock is going to fuck your day up real good.

>>33047795
The hardest part of making a homemade gun seems to be a nice stock based on what I've seen.

>>33041873
>Post says only make one with 18 in barrel
>make joke
>you can't handle joke

>>33047795
It is an old bicylce gun used to shoot dogs that would chase people on bikes

>>33024492
For BP 12ga unhardened water pipe is fine, but you can do a lot better.

>>33024492
you want the heavy duty shit
The black pipe