Heres a harpoon gun that was made quite some time ago, in fact it would have been posted on the old old spudtech forum 9 years ago. Back then coaxial piston valve guns were in their infancy and anything other then PVC was unheard of. I made this in my dorm room at university, power tools and all a visit from security was shrugged off by saying it was a prop for a movie.
No it wasn't made for any practical reason, was only converted to this as the brass gave it a nautical look. It did work, however the broadhead tended to act like an anchor making reeling it in problematic. Edited for content.
Its a 1" bore barrel coaxial with a 2.5" brass chamber. Coaxial piston piloted by a modified brass solenoid valve piloted by blow gun trigger.
The sight was a crosshair made from solder wire, this was done so to aim it in you would just bend it a bit until it lined up a quick easy adjustment.
Its staple diet was not the harpoon (got sick of bending that back straight), spent shotshells are a nice fit in 1" barrel so sliding them down backwards gives a nice fast straight shooting projectile. They could be modified as in the attached pic, I was driving the nails into a concrete wall and the other would pop into a cloud of whatever your loading was. Nice abundant ammo is your a keen shotgunner though you can buy bag fulls for the purposes of reloading if you wanted.
Sadly the gun come to rest in the junk pile and is in a sorry state now, see pic. I'll have to give it a polish up I think.
Edited by jrrdw, follow the posting rules.
Posted: Fri Mar 26, 2010 5:32 am
by chinnerz
o wow! that looks awesome!!
( quote removed by BTB)
have you read the rules?
Posted: Fri Mar 26, 2010 6:20 am
by bradisfun
well it DID look nice... till the efects of age hit
thats a funny excuse for having it but i dont think that it would work for me
Posted: Fri Mar 26, 2010 7:00 am
by Crna Legija
have you posted this before i think i seen it before, none the less it's a beauty
Posted: Fri Mar 26, 2010 7:10 am
by ONEWING
-_- wrote:have you posted this before i think i seen it before, none the less it's a beauty
In jacks landrover thread a week ago or so, before that there was spudtech forum (9 yr ago) then a geocities page with it for many years, until geocities went down recently. So yes its already done the rounds. There were more pictures though these are the only to survive.
Posted: Fri Mar 26, 2010 8:24 am
by deathbyDWV
Ah yes I saw it there too. It looks really cool. How far does or did it shoot?
Posted: Sat Mar 27, 2010 7:23 am
by ONEWING
Hope the mods make everyone send a photo of their cannon up their (Be nice now.. *) to prove its theirs :/ Geez you guys are harsh.
Anyway DWV if your talking about the harpoon itself not that far, maybe 50m, remembering its tethered and requires some weight to carry that line out. For everything else normal piston valve 1" bore distances nothin special there.
(* moderated again buddy..)
Posted: Sat Mar 27, 2010 5:53 pm
by Brian the brain
Ouch.. .Keep it cool ONEWING...
Geez you guys are harsh
Yep...we were just protecting builders rights here..
But I do believe it's all been cleared up now.
Playing by the forum rules helps...
If it makes you feel any better, I loved this thing when I saw it on airpower.net some 6 years ago..It was an inspiration for me back then.
Just so happens that my neighbor shoots 12 Gauge skeet every week and I just asked him for some hulls.
What is the tubing size and type for the hulls?
How accurate did they fly?
Have you tried slicing the tail section?
Posted: Sun Mar 28, 2010 2:27 am
by ONEWING
The barrel is 1" copper, see the pic for the shotshells fit in it.
They flew nice and straight and act like wad cutters, Although I'd typically use "raw" reloading shells that have never seen a crimp.
They are a sliding fit, if you dont want that a bit of tape round the brass section helps. I would think slicing into it can only hurt accuracy.
Posted: Sun Mar 28, 2010 2:59 am
by chinnerz
i dont know man, i think not having a massive scoop on the back of you projectile should aid accuracy..... just sayen....
you should cut some slits into the end of the barrel to act as some sort of defuser, this should also aid accuracy. right??
Posted: Sun Mar 28, 2010 5:11 am
by ONEWING
I'm not going out to say its the "best" thing, only that they are convenient, dont have to make anything they are ready and abundant, adaptable (pic first post), a good fit and their balance makes them fly end on... hang on maybe I am saying they are the best thing, convenience in ammo is of most importance.
I dont like the thought of cutting into something that is concentric and balanced already. And as for the hollow at the back .
Posted: Sun Mar 28, 2010 5:19 am
by chinnerz
convenience in ammo is of most importance.
that is so true man
Posted: Sun Mar 28, 2010 10:07 am
by boyntonstu
The barrel is 1" copper, see the pic for the shotshells fit in it.
Nice fit, is it pipe or tubing? If tubing, type K,L,or M?
They flew nice and straight and act like wad cutters, Although I'd typically use "raw" reloading shells that have never seen a crimp.
The crimp should expand under pressure.
Have you compare both?
They are a sliding fit, if you dont want that a bit of tape round the brass section helps. I would think slicing into it can only hurt accuracy.
Remains to be seen.
This video is interesting but not conclusive:
Posted: Wed Apr 14, 2010 11:33 pm
by ONEWING
I dont know what KLM is so I'm assuming its "pipe".
Suprisingly after sitting outside under a walnut tree for many years the old girl fired up just fine today, after a few bursts of dirty water and dead spiders its good to go.