Trygons

[spaghetti]

Interesting: so you believe that the future belongs to some kind of airguns? I'd say that apart from shooting mechanism, the design of pneumatics is obsolete: same handles and barrel shapes of ten or twenty years ago, while bandguns design show every day something new...

C:\Documents and Settings\RodolfiV\Desktop\purapnea.jpg

 

[foxfish]

Magpie I have to agree that a precharged gun would fit my bill, especially if I was making out the bills, because they would not be cheap. Dont think I have not thought about such a design & talked about their construction. Until a manufacturer sees the light I think we will have to dream. Daystate make one off guns for all sorts of applications for instance tranquilizer dart guns or jungle safari guns all precharged air guns. Expect to pay £2000-10000+ If you want to see a interesting gun in operation have a look at Miles Blue water thread page 17 post 4.
Spaghetti I also agree with you that, it seems, most development is concentrated into rubber powered guns. I love using band guns as it seems particularly satisfying to make a good shot from what is a very basic concept.

 

[Spaniard]

I own a Daystate Harrier, beautiful gun to look at and to shoot.......

 

[foxfish]

I own a Daystate Harrier, beautiful gun to look at and to shoot.......

That's nice mate, do you think we can bore out the barrel & fit a 120 twin barb spear?

 

[Magpie]

Go on Spaniard, let us, we'll give it back afterwards.....(unless it works, in which case you can come over and use it anytime you want)

 

[spaghetti]

This is not last 5 years, but... (click items on the left side menu and enjoy it, my friends)
http://www.apneateam.it/Fucili Storici.htm

 

[Spaniard]

That's nice mate, do you think we can bore out the barrel & fit a 120 twin barb spear?

rofl rofl rofl We could try, telescopic sights are ace; we could shoot bass at 45 yards rofl rofl

 

[Old Man Dave]

Just a quick CAD elevation of an idea for my version of of a 100 cm mamba'ised compressed air gun.

 

[Magpie]

Interesting, is that black bit on the end of the air cyclinder used to compress it? I presume it doesn't use the spear?

 

[Old Man Dave]

Not really, it's more right up your street. I was thinking of using fishing reel technology aka a fixed spool type of line storage.

It's not really that revolutionary, more like a refinement of an existing design.

Loading is still by compressing the captive gas (air) by pushing a piston down using the spear.

The main point is having the barrel mounted on, not in, the resevoir (casing). Just like in a rifle and principally to aid aiming by sighting down the barrel.

I find the biggest deterent to accuracy on my Mamba is the relatively thick body of the beast. My rubber gun with its top mounted spear in plain sight seems to enable me to aim intuetively.

I'd really like to build a prototype. Problem is although I have a lot of kit the handle really needs to be injection moulded out of a plastic (eg HIP) and that equipment I don't have. I do have some super new CAM gear and maybe a prototype would be possible. Probably be a bit utility but for evaluation purposes .....maybe.

Dave.

PS Feeling better Tom?

 

[Fondueset]

I get the impression some of you are talking about guns like the old c02 guns.
The idea is that power be related to loading effort - that's the rule in comps and also one of the things that keeps spearfishing fair. The russian spec ops have a sort of underwater ak that will shoot small spear-like projectiles accurately for 30 meters - why not just get that? I'm sure 30 or so rounds from it would bring down a good sized grouper. Or the old .22 powered smg guns?

Within the loading effort limitation it's interesting to explore this. But I get lost when we start just striving to find the most effective technology for killing fish - what's the point?

 

[sickbugs]

the better u can kill em, the less chance they have of tearing off the spear

 

[Magpie]

The point is because its interesting. I like fiddling with things, understanding how they work and how they could be improved. If humans didn't think like this they'd never have created any of the technology we take for granted today .

Anyway,
So the compressed gas and its piston is in the large cylinder below the barrel. So will you not have to seal the tigger mech? It would have to be completely airtight and pressure resistant wouldn't it? I have't had a close look at the tigger mech of a pneumo gun so don't know if this is right or not, I just can't picture how the pressure can be retained when the spear needs to be locked into the trigger set-up.

 

[foxfish]

I knew it wouldn't take long before someone disagreed with our discussion. well it is a free word here on DB. Personally I think OMD's idea of fitting a small diameter barrel on top of a manually loaded air gun is fantastic. The idea of killing fish cleanly & efficiently appeals to me! I have missed a fair few fish in my 35 years of spearfishing & even worse wounded a few as well. If technology can help me to avoid this I am all up for it. That's my point.
The mamba technology is a big step forward but the gun is difficult to aim any improvements would be great.

 

[Old Man Dave]

Magpie. The piston is in the barrel which is connected to the large chamber (resevoir) via the handle. Yes you're right the whole inside of the top of the handle with the trigger is pressurised. The trigger itself is outside and presses on a pin which passes into the pressure chamber where it operates the trigger mechanism. The pin is O-ring sealed. The handle is a complex plastic moulding containing several seals, which is why it could not be easily made as a one-off. Barrels and therefore pistons are either 11mm or 13 mm caliber (internal diameter). Spears are 6mm, 7mm or 8mm diameter. Air chambers/resevoirs are usually 40mm diameter although the little mamba 90 comes with a 30mm one.

On the principle that a picture's worth a thousand words I'll draw a sketch and post it , soon as.

Just another quickie about my design. Note how high the handle and trigger are compared to the norm where they are underneath the bulk of a traditional gun. This should mean less recoiol "kick" and more accuracy.

Dave .

 

[sickbugs]

interesting deisgn old man, only thing i might see bad about it is that you have quite a tall design, with round sides, which might be bad for drag...and could you use a twin resovoir design for the single barrel? i'll draw a little cross design to show what i mean (please understand that i dont know anything about airguns, pneumatic spearguns, ect, but they do interest me because of how compact they are, even if they all look kind of boring compared to band guns)

i also notice that wood guns, and carbon fiber, are getting wider and wider, seems to be because a gun in this design can swing better laterally?

 

[sickbugs]

pic attached

 

[Old Man Dave]

Sickbugs you're right on.

Not much work has been done on profiling air guns. With the barrel inside the reservoir they're perfectly round and quite good for tracking, however with the barrel outside, on top then some work on making them hydrodynamic would be needed.

Even my design, however, would have cleaner lines than a rubber gun with all those messy bands and you could add on foam or wood shapes or even as you suggast use multiple tubes.

Have drawn a sketch of a standard "barrel inside reservior/casing" air gun to show how a trigger works.

Dave .

Key
Green - plastic handle
Blue – compressed gas (air)
Yellow – water, or in mamba – vacuum
Brown – spear
Orange – casing/reservoir
Dark grey – piston and trigger sear
Light grey – barrel
Pink – air inlet valve
White – trigger, pushrod, handle

 

[Magpie]

Ah, thats a great pic Dave, makes it clear how it all works. I had wondered how the internal reservoir was connected to the piston, which had to be behind the spear or course.
Its quite simple really.
It shows how the trigger would function in your design too as I can see that it would look pretty similar just with a port connecting the lower reservoir to the piston somewhere in front of the trigger.

One thing on the line spool on the gun design though, at the moment you've got the line going back from the spear to the spool, this would make the line fall off the spool unless you had some sort of clip, if you had the line attached to the spear directly above the spool it wouldn't slip off.

 

[Fondueset]

I think you guys are just talking about pneumatics - guns where the loading effort is related to the power. I was thinking you were talking about compressed air guns that expel air with each shot. These would be very simple to build. Theres also a company right now that builds a 15 inch long gun that uses .22 blank charges to fire a short spear - it's intended for finishing off large fish but has a range of about 15 feet. Same as the old .smg guns - but I think a little simpler.

Personally I think pneumatics and roller guns are pretty interesting. I have a little Riffe mt0 I'm thinking about rollerizing at some point - if I can find the stuff to do it the way I want to. I'm surprised the roller approach hasn't taken off more - possibly it's because the guns are not as pretty.