Lightweight cylinder HW 100 carbine recommendation

[Bladerunner too]

I have got one of the older A&M cylinders, and found that without the barrel band the cylinder ‘bends’ so I took it off.

as if I left it on at some point it would break away from the threads to the action weak point and fly away like a bazooka projectile.


Have not decided yet on what to do with it!
I noticed it on the gap between the cylinder and barrel, NOT GOOD.

Aluminium is cheap and easy to machine yes but poor material properties.

Um,makes me wonder if (HW) make the barrel/cylinder band for any specific reason? (tongue in cheek)time.

[sandyman1963]

I am sure I saw HW100 Cylinders on sale on Amazon this afternoon for £60 I thought I’d book marked it but alas I failed.

[Shedder]

I am sure I saw HW100 Cylinders on sale on Amazon this afternoon for £60 I thought I’d book marked it but alas I failed.

They seem to have been on the Evil Bay but the listing has ended now.

[krisko]

Even the titanium alloy ones are welded tubes, so they all can split along that.

[Goatofmendez]

Dear Goat

I have contacted the manufacturer for specification clarity.

Your figures state a wall thickness of 3.5mm in fact it is 4.3mm wall
Material tensile strength is 245 Minimum MPa
Using Barlow Formula you can see a 650 bar without deformation is easily achieved. We did not test to destruction as 650 bar is over double that the tube is rated at. Hope this helps allay any concerns . Any questions get back to me and i can contact the manufacturer further for you.

If the tube that we are talking about is indeed one of ours as this is all hear say though general conciseness and feel from this thread is that it is. How the tube split? is a good question!

Regarding your comment on the test house results.Why would we question a expert in there field in their test results? Who provided full certification? We are not experts in this field are you?

Hi thanks for the reply.

You quote a wall thickness of 4.3mm @ a tensile strength of 245MPa. With these figures I get the deformation pressure as 569.5bar. While I completely concede that this is more than double the working pressure for normal operation, my problem is that on your listings you mention "Rigorously tested & certified to 650 bar with Rapid evacuation and rapid refill in a 10 times cycle, with no deformation or loss of structural strength recorded." This statement flies directly in the face of the 569.5bar deformation pressure calculation using Barlows formula. As scientifically it will deform at 569.5bar.

The answer your question "Why would we question a expert in there field in their test results?" Well, perhaps the fact that one of the cylinders split from end to end at 150bar? I would certainly be questioning them on both counts. You don't need to be an expert to reaslise that there is something wrong when tubes tested to 650bar are splitting at 150bar, do you?

regards
Goat

[sandyman1963]

It makes you think twice about buying after market parts. How many cheap and cheerful things have we all I’m sure bought and found them totally useless and or dangerous.

You do not often hear about bottles and or cylinders going tits up which is reassuring but and it is a big but these thing going wrong can quite literally kill some one.

Nothing is perfect and things do go wrong. It’s good to see that these cylinders are tested it ticks a box.

[Fenton Shooting]

you mention "Rigorously tested & certified to 650 bar with Rapid evacuation and rapid refill in a 10 times cycle, with no deformation or loss of structural strength recorded." This statement flies directly in the face of the 569.5bar deformation pressure calculation using Barlows formula. As scientifically it will deform at 569.5bar.

regards
Goat[/QUOTE]

Hi Goat

Good the hear from you, hope you are enjoying the Christmas festivities.

To clarify and add to your workings out, Posted previously is "Material tensile strength is 245 Minimum MPa"
Minimum being the key word, You're quite right you should work of the Min fraction amount unless proven otherwise. The MPa is achieved when the chemical composition is formed (the makeup of the material is smelted/ cast) to be at a minimum of 245 Mpa upwards from 245MPa is guaranteed.

How to: Proving the material to be certified at a higher MPa
1.Raw material with the same chemical composition batch is acquired from a certified quality assured stock holder with full traceability provided. ISO
2. Machining takes place to a ISO standard
3. Visual inspection takes place for any defects in the machining process.
4. Finishing applied this is when the product is complete.
5. A random % of the products from the batch are sent for testing at a certified test house, this is where the true MPa is found.
If the item would burst at 569.5bar it would be at the minimum of the scale for that cast (batch) when smelted chemical composition when formed. However. If the testing houses findings are of that the 650 bar with Rapid evacuation and rapid refill in a 10 times cycle, with no deformation or loss of structural strength is recorded. This then is the certified MPa / upwards of 245MPa range. As stated the 245MPa is the starting point minimum of the Mpa range from the chemical composition that it was smelted too you can expect from the material. To get the True MPa as i know you are someone that would surely be interested in would be to test until destruction. The figure is then achieved. As 650MPa is over 2 x for Tench 3 x for HW100 Maximum that should be filled too.

6. Upon certification on the batch the tube is then constructed and tested in house to 260 bar (over stressing the tube can create a weakness)

Hope this clarifies the process

Worth covering our position again
This is one the main reasons we have stopped selling the tube only option there is too many factors to go wrong, having the right tools / experience / and safe way to test the cylinder after being built is a risk we are not willing to take. We sell them to Gun shops that are qualified to take the task on. However we feel it is too dangerous. We would like to see other suppliers follow suit or offer a service where they can send the tube to be changed at there facility so it is correctly done and checked safely.

As you grasp the dangers / pressures involved i am sure you will agree filling any tube in your hand is always dangerous and a risk that should not be taken, certainly after never being tested being built by a end user.

Less inexperienced users should be aware of the dangers of alterations modifications to all guns,with help & advice from the shooting community to protect our community from legislation / laws / licensees / annual test certificates from the Ban Everything lobbyists, Everyone's advice can help the whole shooting community.

Merry Christmas

Best Regards
Fenton

[Goatofmendez]

So what is the maximum MPa for 6082T6 Aluminium?

Still can't understand why the tube went pop at 150bar though. Also is it legal to send compressed air cylinders in the post? What postal method do you use?

thanks

[Goatofmendez]

Even the titanium alloy ones are welded tubes, so they all can split along that.

They are not, they are seemless drawn tubes. Where on Earth do people come up with this rubbish?

[krisko]

They are cheaper to get, that’s why. Welded aluminium tubes are also common.
Everybody knows how to milk the hobbyist.

[Blackmax]

They are cheaper to get, that’s why. Welded aluminium tubes are also common.
Everybody knows how to milk the hobbyist.

That's not an answer! And yes, sorry you're totally wrong.

[Luftgewehr100]

That's not an answer! And yes, sorry you're totally wrong.

Blackmax You are absolutely right. Many here e.g. Goatofmendez are only complaining without
even knowing/using/testing these cylinders.

Fenton was the only distributor who answered very detailed and factual to all the accusations.
Ratworks or A&M didn't even write a single word here so a big thump up for Fenton.

Unfortunately my thread went in a direction which I didn't like at all. I esteemed the way Fenton
answered and I trust in their testing therefore I ordered a cylinder. And I am already sure
I will like it.

Merry Christmas

[Blackmax]

Blackmax You are absolutely right. Many here e.g. Goatofmendez are only complaining without
even knowing/using/testing these cylinders.

Fenton was the only distributor who answered very detailed and factual to all the accusations.
Ratworks or A&M didn't even write a single word here so a big thump up for Fenton.

Unfortunately my thread went in a direction which I didn't like at all. I esteemed the way Fenton
answered and I trust in their testing therefore I ordered a cylinder. And I am already sure
I will like it.

Merry Christmas

Nice one buddy, I hope it meets your expectations.

Andy

[Bladerunner too]

So what is the maximum MPa for 6082T6 Aluminium?

Still can't understand why the tube went pop at 150bar though. Also is it legal to send compressed air cylinders in the post? What postal method do you use?

thanks

Are you still confused why the cylinder went pop at the 150 bar? Well maybe it was a tad over 150 bar.and/or been fitted wrong, or maybe i am just suspicious of certain claims.

[mikec4]

The shooter who had the unfortunate experience with the "splitting" air cylinder is a close friend of mine. He is not a beginner with little knowledge of correctly charging air cylinders, but a veteran shooter who just fancied a lighter HW100.
I am sure we can all imagine what it must feel like to have that amount of pressure suddenly vent to atmosphere while holding it in your hand for a charge. In addition to an underpants change, he suffered numbing of his fingers and in my opinion was very lucky not to lose them. At least it split cleanly. I also hate to think of the outcome should the cylinder have turned into shrapnel rather than the clean split. I couldn't believe it when shown the offending cylinder.
Hopefully this item was a rogue. There again, it might not be.
Personally, this will mean, for me anyway, that I will be keeping with the original manufacturers specification for a guns air cylinder. Steel might be heavy, but I haven't heard of one suffering catastrophic damage like this one. I can remember talking to Shaun at I.S.P about the amount of pressure one of his titanium air cylinders was able to withstand, 400 bar plus on testing and still retaining integrity. Obviously then, a correctly manufactured titanium cylinder has the ability to take our normal 200 bar ish pressures without turning into a bomb.
I think that the problem has everything to do with the manufacturing process, obviously. I am not a structural engineer, but from this point I would be very careful about purchasing any none standard pressure vessel. This is unfortunate for those companies who do manufacture high quality and trustworthy cylinders, but, for me, I would never now take any risk.

Finally, this is a serious reminder to all of us who may have become blase about the continual use of highly pressurised air. We all know that our air filling and pressure vessels need to be treated with care and that the slow filling of cylinders is best practice.

Andy

A club member and friend bought this off that there internet web auction site brand new for his HW100. On the first fill, after fitting his spare ends, at 150 BAR it split from top to bottom. He was lucky not to lose his hand. After he had come back from the toilet he rang the supplier. From what I gather they tried to tell him, an ex engineer, that he had over filled it. He got a refund. Motto: Buyer beware. Cheap isn't always best.

Are you still confused why the cylinder went pop at the 150 bar? Well maybe it was a tad over 150 bar.and/or been fitted wrong, or maybe i am just suspicious of certain claims.

So the three of us who saw this know that the member it happened to is a skilled engineer of many years standing, and you are suspicious of the posts we have made?? The wall thickness at the point of fracture is less than 3mm.
Come and have a look if you don't believe us.

Merry Christmas.....