Anyone build their air rifles?

H Wally

H Wally

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What with the massive range of skills on the forum and the wealth of knowledge on the internet, I'm surprised I haven't seen more people building their own air guns. Am I existing in a blind spot to a wide world of home air gun builders or is this something that isn't widely done?

I became interested in DIY airguns researching the Girandoni; it's out of my range cost wise, but it's a very neat concept. Also was quite interested to see similar designs appear in what's thought to be a WW2 italian or austrian Partisan rifle ( http://www.peashooter85.com/post/41246759941/italian-partisan-air-rifle-apparently-this). May also just be someone's fun project or poaching gun. Either way it interests me.
 
No, I just modify the ones I have......putting heavy duty springs in. I got a 177 rifle that will fly through 3/4 plywood.

this is at 20feet. front
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rear
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before the up-grade, the pellets would just burry them selves.
 
That's impressive! Have you had a chance to chrony or calculate muzzle energy? It's a long standing pipe dream of mine to build a mock-girandoni (similar in appearance but modern internally) and shoot BP trail walks with it :)
 
I would love to find or possibly build a big bore air gun too.
Never really looked into it but I envision something in a 38 or larger that would use mini balls or hollow based wad cutters.

Probably stems from a lifelong enjoyment of Sherlock Holmes stories.
 
Its 1230 feet per second. If I "diesel " it, it will go 1520 fps. lots of people don't agree with dieseling but I have heavy duty piston rubbers that can withstand even more . Its as loud as a 22cal rifle. You do need a well built rifle before you attempt this. I had to build a "jig" to re-assemble the gun because of the massive spring pressure. It will go through a standard spruce 2x4. The bullet drop "pellet" is the same as a 22rf @ 100 yards.

the rifle Crosman Optimus .177
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phone book
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the plywood
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metal
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Speaking of dieseling - did some thought in the past on incorporating it as a part of a design

In a basic system similar to those used today, fuel would be either contained in something like a gel cap, baggy, or solid at ambient temperature and would liquify on firing and be inserted along with the projectile. The projectile and this fuel could even be combined into some sort of caseless cartridge.

There would be space immediately behind the projectile for this fuel to be held. Immediately behind that would be a flat or cupped valve similar to an intake or exhaust valve. In theory the compressed air would only act to ignite the fuel behind the projectile, at which point chamber pressure would become greater than resevoir pressure and close the valve separating the barrel and resevoir supply. This would not only focus all the energy of the liquid fuel on propelling the projectile forwards, but would also limit heat and shock to the air system behind. In the event of no fuel being used, the air system would operate normally as the sole supplier of propelling gas.

In theory you could take it one step further and create a system where liquid fuel was injected inline with the gas system by moving the one way safety valve further back in the system and make the fuel injection both variable and controlled by the firing action.
 
There was at least on German made gun that was designed to diesel from the outset. It was spring-piston, with a side tube full of cotton or some similar wadding, into which ether was dribbled, sorta like loading up a Ronson Lighter.
When the rifle was cocked, the air charge was drawn in to the chamber through the ether soaked wadding, providing the fuel source.


It did not sell well as it was a "Firearm" in most places, and it relied upon combustion of a charge to shoot. But it was done. Supposedly tough on mainsprings as well.

Cheers
Trev
 
Interesting. My thought was that the main source of issues from dieseling came from the heat and shock - heat damaging the seals and spring, and shock from sudden deceleration or reversal of direction. I have no idea how stopping a spring short of full travel affects them, but I'd imagine that it does have some effect.
 
trevj said:
There was at least on German made gun that was designed to diesel from the outset. It was spring-piston, with a side tube full of cotton or some similar wadding, into which ether was dribbled, sorta like loading up a Ronson Lighter.
When the rifle was cocked, the air charge was drawn in to the chamber through the ether soaked wadding, providing the fuel source.


It did not sell well as it was a "Firearm" in most places, and it relied upon combustion of a charge to shoot. But it was done. Supposedly tough on mainsprings as well.

Cheers
Trev
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HW Barakuda.
My cousin bought one and had nothing but problems with it.
The leather piston seal would burn away, mainsprings could break, and the 4 "wings" on the piston guide would break off.
Eventually he took the ether injector off and jsut used it as a HW 35.

I later bought it from him, but several parts were lost. I would like to restore it to working condition.


I also have a Daisy VL ""Caseless ammo" airgun.
It uses a 22 solid slug with a yellow propellant molded to the back.
 
The seals I use are heavy duty Neopreme and not sure what the new spring is made from. Its super tuff,..you cant etch it with a file. Rifle has been going strong for 3 years now. No problems. Must have dieseled it hundreds of times already.
 
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tootall said:
HW Barakuda.
My cousin bought one and had nothing but problems with it.
The leather piston seal would burn away, mainsprings could break, and the 4 "wings" on the piston guide would break off.
Eventually he took the ether injector off and jsut used it as a HW 35.

I later bought it from him, but several parts were lost. I would like to restore it to working condition.


I also have a Daisy VL ""Caseless ammo" airgun.
It uses a 22 solid slug with a yellow propellant molded to the back.
Click to expand...

That would be it. Only ever read about them in IIRC, Airgun Digest books, an the odd mention in some of the British airgun magazines I used to buy.

I remember thinking one of those Daisy guns would be pretty cool to have, but they suffered from not quite fitting in anywhere in the scheme of things, and have been relegated to 'also-ran' status now.

Cheers
Trev
 
There was a forum a few years ago called garage gunsmithing on which people used to do build logs of big bore air rifles. One i remember in particular was charged to 2000psi and could fire 3 or 4 50cal. bullets on a fill. There was a YouTube video of him firing it at a bucket and it sounded just like a rifle. I've always wanted to do a 30cal. version but was/am wary of the laws.
 
All these posts and not one safety nazi / outraged legalistic - authoritarian fudd comment. I am amazed.

I had a situation where dieseling was noticeable and on the dramatic side in a common airgun I was shooting some time ago. They say most spring piston airguns often have a small degree of dieseling. It probably happens unless you run your gun absolutely dry, which is not recommended either.

A small caliber 'otato' style gun would be an interesting firearm to experiment with. Legally of course. :rolleyes:
 
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DougP said:
You guys should check out airgunforum.ca - plenty of very knowledgeable people and very interesting mods threads.
- Doug
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I'll check it out - haven't been there, I bet there's some good stuff!

PlaidSon said:
There was a forum a few years ago called garage gunsmithing on which people used to do build logs of big bore air rifles. One i remember in particular was charged to 2000psi and could fire 3 or 4 50cal. bullets on a fill. There was a YouTube video of him firing it at a bucket and it sounded just like a rifle. I've always wanted to do a 30cal. version but was/am wary of the laws.
Click to expand...

Interesting - I'd tend to agree to stick to somewhere in the 30-40 cal range. Without the massively high pressures that's about the range of it without spending most of your life pressurizing it for a single shot.


fat tony said:
All these posts and not one safety nazi / outraged legalistic - authoritarian fudd comment. I am amazed.

I had a situation where dieseling was noticeable and on the dramatic side in a common airgun I was shooting some time ago. They say most spring piston airguns often have a small degree of dieseling. It probably happens unless you run your gun absolutely dry, which is not recommended either.

A small caliber 'otato' style gun would be an interesting firearm to experiment with. Legally of course. :rolleyes:
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Haha- love that it didn't even cross my radar, not being an airgun guy - I didn't even consider that a design would not be considered a firearm - would be used and treated as a firearm, just wouldn't need the powder. Mostly intended to confuse the BP guys on a trail walk :D

Funny you mention the inadvertent dieseling - that's basically how I discovered it myself as a kid - cleaned and oiled the gun and started getting actually noticeable pressure, report and penetration from a very old worn out gun :p
 
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The plastic potato gun researchers are making much of having burst discs between their combustion chamber and the projectile chamber in the barrel. They are also in the habit of calling these: "hybrid guns" when from what I can see, they are still using common gases like propylene, propane, and o2. From what I can tell they are labouriously putting in their burst discs, usually multiple layers of aluminium foil, then screwing the barrel on. From what I can gather they are doing this to get a more uniform start pressure & to get a more efficient burn of their propellant gases. Half of the energy is used up bursting the discs & the other half is available for driving the projectile down range.

airgunforum dot ca is not a bad forum. I go there for the for sale ads. Lately I have been disappointed. Not too many nice guns for sale. It seems there is a glut of pot metal c02 pistols and not much else there. Anything nice like a 1970s or 1960s vintage spring piston air rifle does not last long before they are sold. :(
 
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