SpudFiles

jackssmirkingrevenge wrote:I would definitely like to see a semi/full auto design that can eject cartridges, the latter premise is purely for the "cool" fasctor but after all, that's what spudguns are all about.

Well, I have several different designs for just that, in blow-forward, blow-back, gas operated, recoil, cylinder driven, pump action, minigun...

Ejecting shells was my plan for HEAL's semi auto loader, digging up part of a very old concept I had called "Timberwolf", which I'm sure UKSGC members will remember. The last design I can find of the loader is below:


It was designed to be as narrow and short as possible to keep pilot volume down.
I'd have to make some changes to the plans because Timberwolf was designed to load from below and eject to the side which took some special arrangement of the chamber and valves, and HEAL wasn't made with that in mind, so the magazine will probably have to come out at 45 degrees to the left instead.

Is that a rotating locked breech? Bit overkill for a pneumatic, n'est pas?

A pump action shotgun style launcher with the preloaded carts I had made would certainly have been a feasible undertaking, but my preference would be to make either a BAR style airsoft calibre auto or a marble calibre autocannon.

jackssmirkingrevenge wrote:Is that a rotating locked breech? Bit overkill for a pneumatic, n'est pas?

It is indeed, but it's not as much overkill as you might think, it had a secondary purpose... if only I could remember what it was.

SPG wrote:

Hotwired wrote:@SPG: unknown and unknown but you can take it as a given that it's not for firing pellet sized ammo.

Yeah I just knew you'd say that, but assuming it's not for pumpkins this might just work.

We'll start with the combined barrel/magazine. This is going to just be an extra long barrel, with an end cap on one end and a "hop-up" somewhere along it's length (say 6 or 7 cylindrical ammos worth along). and some ports about 1 ammo length back from this towards the end cap.

Now the chamber, imagine a co-axial gun, but the barrel runs right through.

Now the action. Like a co-ax it relies on a piston moving. But unlike a normal co-ax the piston slides back and forth along the barrel exposing or covering the port.

Voila....

I'm having an odd image of a piston sliding along a barrel of ammo firing each one.

Is that what you mean

If not can you sketch a picture

My holy grails are a waterjet powered rocket car (drools on computer) and a portable safe, and powerful airsoft grenade. Oh yes and a co2 jet pack(pretty much everything in my sig)

Holy grail?

A 20x hybrid. 24" by 4" SCH-160 steel chamber, breech loaded, with interchangeable golf-ball and tennis ball barrels (30 foot golf ball barrel, 20 foot tennis ball barrel). Mount it on its own trailer, with its own barrel support, elevation control, and sideways travel. Give it a recoil absorption system, a polished copper meter pipe with Victor regulators, Some nice U.S. Gauge pressure gauges for measuring chamber pressure, air pressure, and propane pressure, and a pressure transducer to measure peak chamber pressure. And while we're at it, give it spark plug ignition with a nice, professional automotive coil and car battery ignition module. Also, remote ignition, and a 20 pound propane bottle for fuel.

Hotwired wrote: I'm having an odd image of a piston sliding along a barrel of ammo firing each one.

Is that what you mean

If not can you sketch a picture

Close, it follows the co-axial principles of vented pistons etc, but there's one difference. Voila, sorry it's a 2 minute Paint sketch, but hope this helps.

Hmm. Something to consider

I've got a few:

A diesel spring-gun that shoots nails.
A cartridge hybrid of indeterminate caliber (50 cal?)
An auto .22 PCP with rifling for pellets

Basically, anything that is really starting to approach a real firearm in preformance.

Hi,

For me it is:

1) Full Auto. I have a basic design (basically an oscillator that is statically unstable through most of its cycle, and will open and close valves & provide power for a loader). I have no clue what it should shoot with..

2) A practical jet gun: A hybrid where fuel and air are mixed downstream of the valves, and burnt under high pressure. Like a jet engine, where the compressor is substituted by a tank and a valve for a single burst of air. Probablly the greatest challenge is in getting it ignited at all.

3) A sonic golf ball. Possibly the same project as 2).

Regards
Soren

@JSR: I've just looked at that loader again, and it actually twists twice. Now I think back, the design was made to control how the rounds move through the loader to prevent jamming, or the rounds deciding to eject from the side before they were fired.

Well, thinking deeply, if I had to boil my aims down to five projects:

1) HEAL in full 30 bar shell ejecting semi-auto glory.
A 400+ ft-lb semi would be quite impressive, certainly one of the highest pressures for any semi on this forum (if not the highest). Although full auto would be great, I'd want to keep anything like that safely under the control of semi.

2) Full auto combustion 6mm airsoft minigun.
Because I want to shred things with a minigun, what more reason do I need?

3) Plasma cannon
Someone needs to do it, and there are only two people mad enough.

4) 12+ ft-lb 6mm Gauss Rifle
For the fun of watching people's jaws drop when I show them what they thought was science fiction.

5) Preloaded pneumatic cartridge paintball gun.
Pump action, based on some shotgun or other.

You may notice that the only combustion on that list is the airsoft minigun, because I both want to do a proper auto combustion, and because the muzzle flash would be awesome.

Combustions and hybrids don't interest me, and I have no idea why hybrids don't. One of my primary aims is more power (as is most other people's), so why I don't want to build a hybrid has me flummoxed.

Ragnarok wrote: Combustions and hybrids don't interest me, and I have no idea why hybrids don't. One of my primary aims is more power (as is most other people's), so why I don't want to build a hybrid has me flummoxed.

Because in the time that it takes to get the damn hybrid to fire, you could have pumped to 300psi and more

Ragnarok wrote:Combustions and hybrids don't interest me, and I have no idea why hybrids don't. One of my primary aims is more power (as is most other people's), so why I don't want to build a hybrid has me flummoxed.

Ouch, my freakin ears! You must be a sick person Ragnarok seriously, why in Allahs name don't Hybrids interest you?
I know that more power can be achieved through lighter gases and more pressure, but pound for pound a Hybrid would have to out do them all! My Brass Bruiser was made in around 5 hours and has performance similar to a handgun, blah blah blah......

Edit: Mopherman, with my bruiser i can get off about 3-4 shots a minute! Try pumping that fast. I do have a $10k compressor at my disposal though

Edit Edit: I can get about a shot every 90 seconds with this one (700ml or about 14 eggcups)


Thankyou MrC

mopherman wrote:Because in the time that it takes to get the damn hybrid to fire, you could have pumped to 300psi and more

Joking aside, what is a practical ROF for an average burst disc hybrid? Not Nova's little thing that's the size of an eggcup, impressive though it is.

Hopefully in a few months I'll have built a custom compressor that from a standing start should be able to get HEAL up to a full 30 bar in about 30 seconds. If I chose to, it could also boost an input from a helium bottle regulator, most of which won't do those pressures.
That should create similar power to a 4 to 5x hybrid (although without the supersonic capability) in under half a minute, with power levels (using air) of 400+ ft-lbs - over 500 with heavier ammo.
Helium would give me 500 to 600 capacity, and that would give hybrids some real competition.

@Nova: I don't particularly like the idea of hybrids, I have no idea why. If I had to guess, I'd have to say it was a combination of concern about failure, practicality problems, as well as the fact that I just don't like burst discs, and making a piston hybrid has it's own set of problems.

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