Girandoni hybrid

[DT Fletcher]

So, then I agree that we've only seen on of these Heiberger airguns with a Girandoni style mag barrel attached. I have already pointed that there are other Heiberger's with straight barrels. I'm sure if some effort was put forth, we would find more of them.

Good to know that the info was from Beeman. Sounds exactly like something he would come up with and goes to explain why I jumped on it. Normally, I avoid any contact with Beeman's fiction writing.

Certainly sounds like this airgun is in the right hands. Just hope that he fully understands the important safety issues involved in operating these airguns.

[Garvin]

Certainly sounds like this airgun is in the right hands. Just hope that he fully understands the important safety issues involved in operating these airguns.

He's using it with CO2 and since Lawrie is 'Mr CO2', I'm sure it's very safe.

[DT Fletcher]

He's using it with CO2 and since Lawrie is 'Mr CO2', I'm sure it's very safe.

Nonsense. The safety issue with these airguns has absolutely nothing to do with what is being used to power it. These guns, if not properly understood, can be deadly. And, the problem is exactly as you allude to, people think that they know airguns so well that there is nothing new to learn.

The lack of understanding of this type of airgun is near universal today. Beeman clearly doesn't have any idea how these guns work. I've talked with guys who have made reproductions of these airguns and they have no clue how dangerous these airguns are.

I can only do so much. At some point, somebody is going to get killed or seriously hurt if a better understanding of these extremely dangerous airguns is not achieved.

If somebody would make a video demonstrating how dangerous this airguns are, I would back off a bit and just point to that video,. Until then, I will continue to be a pest about this.

[mrto]

I would have thought gunsmiths who have made reproductions of this type of gun have a very clear understanding of the design's inherent flaws and potential dangers.After all,the valving design is very simple,just a knock open valve against valve spring tension and ambient reservoir air pressure.

https://www.youtube.com/watch?v=5fRu5tYH-4Q


Have you fired one of these?

I do wonder if the decocking,(because of the design I agree should not be done) of the mechanism when the cylinder is at 'full' pressure will always result in an unintended and dangerous discharge or if the likelihood of this happening increases only after shots have been fired and cylinder air pressure has decreased allowing hammer spring strength to overcome valve spring and cylinder air pressure resistance,if the hammer is inadvisedly decocked?

Whether and at what point this may happen would vary from gun to gun by maker depending on the balance of the valving mechanism employed?

I'm sure Lawrie Amatruda is fully aware of the dangers of this gun whether it is powered by compressed air or indeed even maybe especially in Co2 because of the lower cylinder pressure.

Possibly Lawrie could comment?

[DT Fletcher]

I would have thought gunsmiths who have made reproductions of this type of gun have a very clear understanding of the design's inherent flaws and potential dangers.After all,the valving design is very simple,just a knock open valve against valve spring tension and ambient reservoir air pressure....

You have demonstrated exactly what I'm talking about: Because you understand modern airguns, you also think you understand these old airguns. But you don't. I know this is so because your description of the valve is completely wrong. It is NOT a knock open valve, which is what a modern airgun valve is. It's what Wolff calls an indirect trip battery. The hammer action does not rebound off the valve stem like a modern gun, instead it first strikes open the valve, always the exact same amount, and then travels past the valve. This is nothing like a modern airgun, no modern airgun has this type of battery action (with one or two very rare exceptions.) Has inherent dangers completely different from modern airguns.

I have seen animations of this valve on Youtube where they have the hammer bouncing back off the valve. Nonsense, the hammer always travels past the valve stem. Note: this is one of unique characteristics of the indirect trip battery, no matter how fast the hammer is traveling, the valve always (repeat ALWAYS) opens the exact same amount (there might be some variation due to tank air pressure and resistance of the valve to being moved) but, in general, the valve opening is set. There are variable power versions of this airgun but only one example is known to exist ) in Girandoni's home town no less.

[DT Fletcher]

Note: this video ( http://youtu.be/5fRu5tYH-4Q) looks okay. Note how the tumbler, after opening the valve, proceeds past the valve stem; i.e. an indirect trip.

Now reimagine this action with the hammer being moved very slowly, as slow as possible, note that the valve will be moved the same as if it was going full speed. Where this valve has been used in modern airguns is with target guns (described to me, I have not seen these myself) where the designer used exactly this type battery. The purpose was to use it as a means of power regulation. No idea if the designer of the modern version even knew of the old version.

[mrto]

Note: this video ( http://youtu.be/5fRu5tYH-4Q) looks okay. Note how the tumbler, after opening the valve, proceeds past the valve stem; i.e. an indirect trip.

Now reimagine this action with the hammer being moved very slowly, as slow as possible, note that the valve will be moved the same as if it was going full speed. Where this valve has been used in modern airguns is with target guns (described to me, I have not seen these myself) where the designer used exactly this type battery. The purpose was to use it as a means of power regulation. No idea if the designer of the modern version even knew of the old version.

On this page can be found about halfway down excellent diagrams of the Girandoni mechanism,which clearly show it as a type of knock open valve,

https://www.beemans.net/Austrian%20airguns.htm

The slightly more elaborate design of the mechanism necessitated because the air source and valve are positioned to the rear of the lock which is of relatively conventional flintlock design.

Also,I have found this youtube video of the Girandoni replica being decocked which is consistent with my understanding of the mechanism and answers my questions admirably.

https://www.youtube.com/watch?v=qvy2OunCu9w

[Garvin]

Nonsense. The safety issue with these airguns has absolutely nothing to do with what is being used to power it. These guns, if not properly understood, can be deadly. And, the problem is exactly as you allude to, people think that they know airguns so well that there is nothing new to learn.

Hmm. I wasn't pointing out that co2 was safe, just that Lawrie is using co2 and he's a real expert in using this gas, so he will understand how safe the gun is, or otherwise, probably better than anyone else alive.

[Geezer]

Normally, I avoid any contact with Beeman's fiction writing

lol.