280cc bottle or Cylinder options

[Squinty]

Had bit of a moment last week and bought a 177 FX superior liner.
Couldn't see the point of spending £175 on an LW and chopping off 8"

Plan is to make up a lightweight shrouded barrel to go on my spare Mk2 block and thats when I got to thinking about shroud diameter.
A bottle would allow 25mm, with a cylinder possibly 35mm?

What are the available options in relation to capacity?
looking for a genuine QF reg, but ideally removable.

[angrybear]

Having measured mine with the std shroud (25mm) & 50mm dia bottle, 28mm would definitely fit, 30mm might but would only have around 0.5mm clearance.

AFAIK 50mm bottles are 200/280/380cc's, as for tubes FX do 185/220/250/290cc's, no idea about other brands, but I guess any could be made to fit.

[Squinty]

Thanks Mr Bear.
Will attempt to copy Bucketboys ER collet fixing method
28mm would give more room to clear the collet nut.
I found the FX dreamline FAC tubes, think they're the longest but as with everything FX  .. there are a list of options.

[Millingman]

Hello squinty, I like your went down this route with the er16 collets and superior fx liners, I'll be honest the collet method worked but was a complete pain in the neck. What I now do with the fx liners is use a tensioning system. There's a few guys on you tube adopting this on there impacts with liners upto 800mm long. You can basically pick the rifles up by the barrell with no zero shift unlike the collet method. Ernst row on youtube and
airarms hunting guy will give you a better understanding etc. I can't be bothered with all the hassle of lw blanks etc. Hope this helps.
Ernest Rowe fx airgun barrel tensioner system install.
It gives you an idea of what you will need, if you have access to a small lathe you can easily make the brass bit that goes into block.

[Squinty]

Thanks for the pointer,- I'm flying by the seat of my pants on this.
Part of the fun I guess, rarely done things the easy way

intention is/was to  fix sleeve the liner and support inn carbon shroud in the same way that a 10mm blank would be.
No compression beyond the collet holder, maybe the opposite sleeve and tension the liner <> instead of ><.

[Millingman]

Those er16 collets ar extremely hard, machining them which you will have to do to accommodate the liner is a nightmare, bucketboy if I remember turned a collet out of delrin to avoid damaging the liner, another horrible job on the lathe. My tensioned system is carbon fibre 20mm o/d 14mm id with a 14mm metal tube inside, it can the be torqued at muzzle end hard onto the rapid block. It's very very rigid without any stress on the liner. I'll try and get some photos for you.

[Squinty]

all ideas and practical methods taken on board although I'm struggling to see how theres going to be much volume in the shroud

[Millingman]

You are correct my tensioned system has no volume whatsoever, if you look at fx maverick barrel tensioner kit install on you tube this might be a better option if your needing to strip air etc.
Hope this helps. I'm a great fan of fx superior liners, very very accurate and cost  effective, I use them on all my rapid variations apart from one.

[Squinty]

Do all of the liners have such tight chokes?
Just rodded a few pellets through it, dead stop an inch from the crown.

Cheers I'll look at the Maverick vid

[Millingman]

I believe even the heavy slug liners are choked.
I'm using jsb diablos 15.89 5.52s, the superior seems to like them and the fx hybrid 22g slugs

[Squinty]

They're on par with some of Theobens infamous in-house chokes 

The maverick kit looks as if the volume is significantly reduced too.
I have a new A4 pad- this may need copious amounts of tea.

[Millingman]

Gives you an idea of what's involved with a tensioned system, this was a prototype before I made the final system, the brass section is a lot longer than a standard mk1 or mk2  block, i have custom blocks that are longer at the front etc the 14mm steel tube screws onto the brass section with the liner running through. The thick carbon tube slides over to hit the block then torqued down at muzzle. I've got a big a&m moderator on so no need for me stripping air through a shroud. The only problem i had with the er16 method of fixing a liner was zero shift everytime I used the gun.

[Squinty]

cheers, food for thought.
I think once trimmed down to 16" using a 1 pice collet holder as the base for fixing the block cap and and 28x2 shroud should be stiff enough.

16mm o/d ER-16M version not 12mm shown