preloaded pneumatic cartridge

Show us your pneumatic spud gun! Discuss pneumatic (compressed gas) powered potato guns and related accessories. Valve types, actuation, pipe, materials, fittings, compressors, safety, gas choices, and more.
User avatar
jackssmirkingrevenge
Five Star General
Five Star General
Posts: 25836
Joined: Thu Mar 15, 2007 11:28 pm
Has thanked: 157 times
Been thanked: 94 times

Donating Members

Sun Jul 24, 2011 4:34 pm

warhead052 wrote:Wait, so if you pull back on it, how are you going to make a gun that will actually use them? Some sort of pneumatic piston that pushes them forward or something?
A spring loaded hammer, something like this:
Attachments
vlcbreech.PNG
vlcbreech.PNG (6.52 KiB) Viewed 3591 times
hectmarr wrote:You have to make many weapons, because this field is long and short life
User avatar
jor2daje
Specialist 4
Specialist 4
Posts: 418
Joined: Sun Oct 05, 2008 9:41 pm
Location: Southern California

Fri Sep 02, 2011 1:39 am

just throwing a reply in here to say its looking great jsr and to make sure I get email notifications haha
Patience is a virtue, get it if you can, seldom in a women, never in a man.
User avatar
LovableAirGuns
Specialist 2
Specialist 2
Posts: 267
Joined: Tue Sep 28, 2010 5:58 am

Fri Sep 02, 2011 5:58 am

Very keen to see thus finshed, its looking good.
User avatar
jackssmirkingrevenge
Five Star General
Five Star General
Posts: 25836
Joined: Thu Mar 15, 2007 11:28 pm
Has thanked: 157 times
Been thanked: 94 times

Donating Members

Sun Sep 11, 2011 12:38 am

Just a niggling thought, converting a 7.62/308 cartridge to pneumatic using a 7mm OD tube insert:
Attachments
cartconversion.PNG
cartconversion.PNG (23.56 KiB) Viewed 3446 times
hectmarr wrote:You have to make many weapons, because this field is long and short life
User avatar
jhalek90
Specialist 4
Specialist 4
Posts: 498
Joined: Fri Aug 14, 2009 5:37 pm

Sun Sep 11, 2011 1:27 am

you last videos look like a much more complex version of what i did over a year ago.

Take a female quick disconnect, and remove all the internals except for the rubber washer, and the bearings.... it will hold a 7/16'' steel ball air tight.

I have taken that design up to 350 psi... the only problem i had, was pulling the sleeve back at higher pressure. Your idea of using a hammer to move the sleeve is excellent. I now want to revisit my design.

Thanks!
jackssmirkingrevenge wrote:I wonder... if you put flammable vapours inside a lady... could you get her to diesel?
POLAND_SPUD wrote:Anything is possible with the proper 3-way valve.
User avatar
LeMaudit
Corporal 2
Corporal 2
Posts: 665
Joined: Thu Apr 16, 2009 2:48 pm

Donating Members

Sun Sep 11, 2011 6:36 am

Did you got some inspiration from here ? ;-)
I HAZ A BANG!
User avatar
jackssmirkingrevenge
Five Star General
Five Star General
Posts: 25836
Joined: Thu Mar 15, 2007 11:28 pm
Has thanked: 157 times
Been thanked: 94 times

Donating Members

Sun Sep 11, 2011 6:51 am

LeMaudit wrote:Did you got some inspiration from here ? ;-)
Totally :roll: :D

Doing some prototyping in the meantime, another pop at the hybrid cartridge and a decent fill rig.
hectmarr wrote:You have to make many weapons, because this field is long and short life
User avatar
jackssmirkingrevenge
Five Star General
Five Star General
Posts: 25836
Joined: Thu Mar 15, 2007 11:28 pm
Has thanked: 157 times
Been thanked: 94 times

Donating Members

Tue Aug 07, 2012 12:46 am

Something which came out of this visit, I got to look at a Korean air cartridge rifle from the 1950s. They work on the same principle as the Saxby Palmer air carts, basically a hammer valve where the hammer smacks the bottom of the cartridge pushing it against the valve.

This is the English variation:

Image

Image

This is the one I saw yesterday, bigger internal volume and apparently in the 50 ft/lbs range...
Attachments
aircartridge.jpg
hectmarr wrote:You have to make many weapons, because this field is long and short life
iknowmy3tables
Staff Sergeant
Staff Sergeant
Posts: 1571
Joined: Fri Dec 15, 2006 3:57 pm
Location: maryland

Wed Aug 08, 2012 7:21 am

I really like the idea of a large hammer valve that also acts as the check valve for filling, however I've never seen any of us use a fill valve that wasn't a quick connect or a Schrader
User avatar
jackssmirkingrevenge
Five Star General
Five Star General
Posts: 25836
Joined: Thu Mar 15, 2007 11:28 pm
Has thanked: 157 times
Been thanked: 94 times

Donating Members

Wed Aug 08, 2012 11:25 am

iknowmy3tables wrote:I really like the idea of a large hammer valve that also acts as the check valve for filling, however I've never seen any of us use a fill valve that wasn't a quick connect or a Schrader
Looks like you missed this ;)
hectmarr wrote:You have to make many weapons, because this field is long and short life
User avatar
jackssmirkingrevenge
Five Star General
Five Star General
Posts: 25836
Joined: Thu Mar 15, 2007 11:28 pm
Has thanked: 157 times
Been thanked: 94 times

Donating Members

Sun Dec 20, 2015 3:50 pm

Revisiting this idea in my head, looks to me that a variation of the Saxby Palmer with a balanced spool would make a lot of sense. There's still the o-ring friction but nothing like the force of keeping a poppet type valve closed, which would mean less force to open it, so the bolt spring might be weak enough to allow for shell ejection and therefore potentially semi/full auto fire...

Image

edit: alternative configuration with greater internal volume:

Image
hectmarr wrote:You have to make many weapons, because this field is long and short life
User avatar
wyz2285
First Sergeant 2
First Sergeant 2
Austria
Posts: 2381
Joined: Sat Mar 06, 2010 7:50 am
Location: Porto, Portugal
Has thanked: 1 time
Contact:

Mon Dec 21, 2015 5:20 am

You would have to reverse the fill plug on the last design.
CpTn_lAw wrote: :D "yay, me wanna make big multishot pnoob with 1000 psi foot pump compressor using diamond as main material. Do you think wet bread make good sealant? " :D
User avatar
jackssmirkingrevenge
Five Star General
Five Star General
Posts: 25836
Joined: Thu Mar 15, 2007 11:28 pm
Has thanked: 157 times
Been thanked: 94 times

Donating Members

Mon Dec 21, 2015 6:59 am

Oh no it's one of these:

Image

Wonderful things, if only I had discovered them earlier.
hectmarr wrote:You have to make many weapons, because this field is long and short life
User avatar
jackssmirkingrevenge
Five Star General
Five Star General
Posts: 25836
Joined: Thu Mar 15, 2007 11:28 pm
Has thanked: 157 times
Been thanked: 94 times

Donating Members

Mon Aug 22, 2016 11:46 am

Some more idle musings, combining the locked projectile "valveless" design with a balanced spool. The problem with the latter is that even in small calibers, beyond a certain pressure it becomes far too difficult to actuate when made like this, however if you incorporate in a system where the friction is being balanced out in the opposite direction it should make it relatively easy to fire without too much effort.
valvelessbalabced.png
valvelessbalabced.png (12.6 KiB) Viewed 1994 times
hectmarr wrote:You have to make many weapons, because this field is long and short life
User avatar
jackssmirkingrevenge
Five Star General
Five Star General
Posts: 25836
Joined: Thu Mar 15, 2007 11:28 pm
Has thanked: 157 times
Been thanked: 94 times

Donating Members

Tue Sep 26, 2017 4:13 am

Something interesting on this subject, there is a company called Inovairtech making Magnum Air Cartridges made for larger bores (0.257"-0.40") with some impressive performance characteristics, exceeding 100 ft lbs of energy for most projectiles.

There is nothing particularly innovative about the cartridge mechanism, it's a balanced spool that is hollow, hammering the base of the spool exposes ports at the rear which allows the air to vent through the hollow spool into the barrel:

[youtube][/youtube]

Image

This is virtually identical to the airsoft APS APM50 cartridges:

Image

The difference is obviously the volume and the pressure, they can take up to 4500 psi.

Another clever feature is the head shaped like a quick connect fitting which allows for rapid filling without the need for a complex fill rig:

Image

Overview of one of their single shot rifles:

[youtube][/youtube]
hectmarr wrote:You have to make many weapons, because this field is long and short life
Post Reply