300 bar conversion to 232 bar filling

[jepho]

I am just in the process of buying a Feinwerkbau 700 Evolution Top 10 metre match rifle. The shop had no way to fill the tank but did have the Feinwerkbau filling adaptor with the gun. It has 5 male threads denoting it was a fitting for 232 bar cylinders. The 300 bar cylinders require 7 threads on the male end of the adaptor to fill the cylinder filling point without letting any air escape.

I made a call to Best Fittings and they sold me the linked item and fitted a quick release fitting for a standard hose. Job done.

https://www.bestfittings.co.uk/shop/...e-18-bsp-male/

The overall cost including first class postage was just £24. Fantastic service and I spoke with Tracy during several calls, just to confirm that I was buying the most suitable items. Very helpful and a big shout out to Best Fittings. I have never used them before and I have no connection to the company. It is great to see that customer service is alive and well. Highly recommended and saved me buying a 232 bar cylinder.

[GrahamHenderson]

surely you only needed this much cheaper adapter ...

http://www.bestfittings.co.uk/shop/a...g-solid-brass/

[junglie]

Yeah but it's for a feinwerkbau innit? LOL

[jepho]

Yeah but it's for a feinwerkbau innit? LOL

[Jesim1]

Hi Jepho

I had to read this thread a couple of times to get my head round it and now I understand that you already have the charging gear, but not the correct adaptor for your new Feinwerkbau to connect direct to the cylinder, so you had two options - 1. Is the option you chose for a quick release adapter so you can use it with your existing kit, or 2. Which is the cheap spacer that would allow you to use the Feinwerkbau filling adaptor that came with the gun?

This is also true on the HW100 with the two brass fittings it comes with, but no spacer!

I've read a couple of you posts now, so welcome to the forum, you seem quite a switched on guy

Enjoy.

James

[RobF]

I’ve owned several pcp’s with removable cylinders, Anschutz, Steyr and Walther. Walther are the only ones I know who supply a 300 bar adapter in the box. That said I believe they are also the only ones who allow a fill (on their steel cylinders) to 300 so perhaps it’s a case of other makes not wanting you to connect a 300 bar source to a 200 bar cylinder.

[jepho]

Hi Jepho

I've read a couple of you posts now, so welcome to the forum, you seem quite a switched on guy

Enjoy.

James

Hi James;
Thanks for the welcome. Dunno about switched on... I have waited all my life to be an old curmudgeon and I wont be denied now I am an old fart.

[RobF]

surely you only needed this much cheaper adapter ...

http://www.bestfittings.co.uk/shop/a...g-solid-brass/

Then you'd still only have 5 threads holding the adapter in place. There's a reason they have 7 in 300 bar, and there's a reason they test for thread stretch when cylinders are tested.

[krisko]

That model airgun has 200bar fill pressure. Are you trying to fill it to 300bar?

[RobF]

That model airgun has 200bar fill pressure. Are you trying to fill it to 300bar?

No he's trying to fill it from a 300 bar cylinder.

[jepho]

That model airgun has 200bar fill pressure. Are you trying to fill it to 300bar?

Absolutely not. I know that it has a 200 bar fill pressure and I want to fill it from my 300 bar cylinder.

[jepho]

Then you'd still only have 5 threads holding the adapter in place. There's a reason they have 7 in 300 bar, and there's a reason they test for thread stretch when cylinders are tested.

Excellent point.

[angrybear]

Then you'd still only have 5 threads holding the adapter in place. There's a reason they have 7 in 300 bar, and there's a reason they test for thread stretch when cylinders are tested.

While factually accurate, none of the components between the cylinder outlet & the rifle should ever experience anymore pressure than the rifle max fill because that's when the cyl valve gets shut.
That's why the DIN airgun charging kits have a 225bar swp rather than 300bar

A point that anyone thinking of buying a rifle that fills above 225bar needs to note.

[Jesim1]

While factually accurate, none of the components between the cylinder outlet & the rifle should ever experience anymore pressure than the rifle max fill because that's when the cyl valve gets shut.
That's why the DIN airgun charging kits have a 225bar swp rather than 300bar

A point that anyone thinking of buying a rifle that fills above 225bar needs to note.

Having dealt with compressors and dive cylinders for years in the dive industry this was all too apparent to me when I got back into air guns, and there is a general "ignorance" about all things pressure related which is a bit scary when reading some of the posts I see. An example of this is people being told to buy "adaptor blanking plugs" so they can seal off their charging whip to see how much pressure in in the cylinder - which can be upwards of 300bar being used on a 232 bar "well used" whip

I have no issue with differing opinions to mine, but it is another matter when the advice given is potentially dangerous

James

[RobF]

While factually accurate, none of the components between the cylinder outlet & the rifle should ever experience anymore pressure than the rifle max fill because that's when the cyl valve gets shut.
That's why the DIN airgun charging kits have a 225bar swp rather than 300bar

A point that anyone thinking of buying a rifle that fills above 225bar needs to note.

DIN is not limited to 200 bar. You can buy 300 bar DIN kit. With the right kit the 300 bar DIN will fit a 200 bar bottle.

There's a difference between should ever and can ever ... In other words if you didn't shut off the valve when you should have, at 200 bar, then the whole system can get to 300 bar, or certainly over 200 bar. The 300 bar dive cylinder won't shut off when the gun cylinder gets above 200 bar automatically, you have to do that bit yourself. The gun cylinder won't shut off automatically either. With some cylinders varying enormously in how fast they can deliver that pressure there's always that chance it won't be closed when it should have been, which is when 5 threads might not be enough.

Max rifle fill pressure on a Walther LG300 steel cylinder is 300 bar, so it's entirely possible to exceed 200 bar with a 200 bar adapter and still be in spec of both cylinders... except Walther supply a 300 bar DIN adapter with 7 threads.



I suspect the tolerances on the thread spec is well over what you need for 200, but then I also suspect they're there for a purpose, ie when you have more than 300 bar for some reason (like a hot day on a fresh 300 bar fill that was done at much colder temp).