300-600psi piston valved pneumatic.

[SpudFarm]

This is a gun I have had for quite some time but I haven't posted it yet.

Enough small talk;
Barrel: 90cm of 5mm ID brass tube for pellets and small slugs.
Barrel2: 100cm of 4mm ID brass tube that is sleeved inside the bigger barrel to fit the breech.
Valve: Barrel sealing Tee housed piston valve.
Chamber: 1/2" stainless steel coupling with other fittings seen in the pictures.
Pressure gauge: Argon regulator tank pressure gauge, it measures from 0-315bar (about 4600PSI) However it's accuracy is disputable at such low pressure. It tells me 30bar but I think it is higher, I may be wrong.
Pilot: 3/8" ball valve, I want to make a push button valve but I am still puzzling with designs.
Filling: Shock pump, hopefully fridge compressor in the near future.

This gun has been used alot lately, and I like it very much.
It has a solid stainless steel piston made from a umbraco screw head housed in a bored out 3/8" pipe nipple that seals against a brass seat.

The OD of the seat/breech pipe is 8mm and it is soldered into a 1/4" brass nipple. The pipe was bored out to 6.5mm to fit my barrel, however the boring is just a inch deep so it wont touch the piston.

There really isn't much more to it, I made it from spare parts so I had something to use my pump on.

I think it has a decent velocity (Not measured) since it can blast cola cans right open and make apples go good bye with airgun pellets.

Some pics:


Breech assembled. I will make a locking mechanism when I get a good trigger.


Chamber and valve.


Pressure gauge.


Gun and pump, best friends.


Apple shot at (gauge says) 30bar with a pellet.


Apple puzzled together and a cola can that was filled with water with same ammo and pressure.


Closeup of entrance hole.

Vids:

[youtube][/youtube]
[youtube][/youtube]
Note that I just put the gauge on and the earlier shots was at guessed pressure.
The apple and cola can was with gauge.

Ask if there is something you wonder about

[jackssmirkingrevenge]

Ah look who's back from shopping

Very nice, sometimes it's cool to build long barreled launchers as testing rigs

[SpudFarm]

Ah look who's back from shopping

Haha, you evil bully!

Very nice, sometimes it's cool to build long barreled launchers as testing rigs

You think 1m is long? Well that makes me think..

I have actually thought about making the barrel longer, allows me to fire heavier projectiles at acceptable speeds.

This is what evolved from the piston hybrid that never worked so the plan is still to get it in a stock.

[jackssmirkingrevenge]

Haha, you evil bully!

Hey I'm not the one who's pussy whipped

You think 1m is long? Well that makes me think..

I get my barrel material in 1 metre lengths, I was thinking of grafting two 6mm barrels together for a hybrid testbed...

[Fnord]

It tells me 30bar but I think it is higher, I may be wrong.

Don't worry, pressure accuracy within a couple hundred psi is acceptable to most of us!

Very nice, sometimes it's cool to build long barreled launchers as testing rigs

I know!

[jackssmirkingrevenge]

I know!

Of course "long" is relative

Also, as a preemptive strike, that is NOT what she said

[mark.f]

Of course, I believe only a male would be inclined to make excuses like that.

Great job, spudfarm. Any chance of using a hydraulic source like a modified bottle jack base and an air displacement cylinder for 4500 PSI shots?

[SpudFarm]

Hey I'm not the one who's pussy whipped

Where can I get away from this?! My friends keep telling me to

I get my barrel material in 1 metre lengths, I was thinking of grafting two 6mm barrels together for a hybrid testbed...

I am using the same pipes as you are using, they only come in 1m lengths but they are very cheap and within good dimension tolerances so different sizes can easily be used to make a solder joint on the middle.
Atleast in Norway, there is a short supply of solder in epoxy kingdom..

Great job, spudfarm. Any chance of using a hydraulic source like a modified bottle jack base and an air displacement cylinder for 4500 PSI shots?

Might be within reach. However I will use hydraulic fittings and make a Tee valve. I was a exchange student at a machining shop recently. I got along pretty well with the owner of the company so I might get some help with machining.

Well, I just fired a slug into a stack of magazines. I modified the slug so that it would disperse the most possible energy in the target and I succeeded! Rarely happens!

[youtube][/youtube]

[FighterAce]

Any pics of the piston?

[SpudFarm]

Any pics of the piston?

The piston is just a cylinder of steel with a sealing face glued to it. Getting pictures of it will be troublesome because the entire gun is loctited together.

I can try tomorrow.

[jackssmirkingrevenge]

Where can I get away from this?! My friends keep telling me to

Easy, stop regarding the female gender as the "fairer" sex, and women as deities somehow worthy of veneration - instead treat them as the banal irrational creatures that they are. In epoxyland we have an expression that translates literally as "kick them and they will come", and odds bodkins, it works!

I wish someone was around to give me that advice when I was an adolescent

Any chance of using a hydraulic source like a modified bottle jack base and an air displacement cylinder for 4500 PSI shots?

I could do that hooking a burst disk launcher directly to my scuba tank when its full...

different sizes can easily be used to make a solder joint on the middle. At least in Norway, there is a short supply of solder in epoxy kingdom...

This is how I would do it, using a drill bit or similar to keep things centered, adding a sleeve and filling the space between sleeve and barrel with epoxy:

[SpudFarm]

Easy, stop regarding the female gender as the "fairer" sex, and women as deities somehow worthy of veneration - instead treat them as the banal irrational creatures that they are. In epoxyland we have an expression that translates literally as "kick them and they will come", and odds bodkins, it works!

I wish someone was around to give me that advice when I was an adolescent

I don't know why but sometimes things you write give no sense whatsoever but I still recognize the situation
Time to kick some arse then!

I could do that hooking a burst disk launcher directly to my scuba tank when its full...

I guess I could make a assembly of fittings to connect a gun to my inert gas welding tank to but damn that would be nerve wrecking the first time used!

This is how I would do it, using a drill bit or similar to keep things centered, adding a sleeve and filling the space between sleeve and barrel with epoxy:

Why not get a pipe that fits perfectly outside your barrel and sleeve the two barrel sections inside that? Solder or epoxy and you are done, much easier
However you might be better with Epoxy and "Function over form!"

[jackssmirkingrevenge]

I don't know why but sometimes things you write give no sense whatsoever but I still recognize the situation

Some less vague advice, some of which is useful, if only for the sake of challenging your perception...

I guess I could make a assembly of fittings to connect a gun to my inert gas welding tank to but damn that would be nerve wrecking the first time used!

Not just the first time I'll wager

Why not get a pipe that fits perfectly outside your barrel and sleeve the two barrel sections inside that? Solder or epoxy and you are done, much easier

I assumed that a perfectly fitting pipe might not be available, as more often that not I tend to work from a stock of material instead of purchasing specific parts for the project at hand.