Pro Sport compression tube

[Kuberboef]

It's not much mate, ask Charlie PS.177 - I;d suggest that a far better tune for the PS is a 23/22mm sleave down and sleave the port too...

Hehehehe

Planning a sleeve down to 23mm with a Tx, my PS is holy and you don't touch it!
But a short stroke piston is on it's way.
Was a little tricky to design, you want exactly 13mm longer, but you must make the piston 13mm longer in the PS too
otherwise you beartrap stops working.
Now with the HW type seal the front is longer and there is a millimeter or two of seal material in front, that the standard PS doesn't have.
So your measurement must be from the front, with the seal on, to where it latches on the latching rod, not to the end.
That must be 13mm longer.

Anyone else have ideas?
Input?

I will probably not sleeve it down but make a new comp tube from silver steel.
Have it case hardened, chromed and honed properly.

[rockdrill]

Planning a sleeve down to 23mm with a Tx, my PS is holy and you don't touch it!

The sleeving will make a bigger benefit on the PS than the TX, both in terms of firing cycle and making it nicer to use given it less user friendly cocking system.

[Kuberboef]

The sleeving will make a bigger benefit on the PS than the TX, both in terms of firing cycle and making it nicer to use given it less user friendly cocking system.

When sleeving it, do I shorten the stroke too?

[rockdrill]

Jon would need to answer that one, he knows a whole lot more on these modifications than I do.

[Kuberboef]

Jon would need to answer that one, he knows a whole lot more on these modifications than I do.

Calling Jon???

[brucegill]

Calling Jon???

have a look here mate:
http://www.airgunbbs.com/showthread....-my-22mm-setup

[Kuberboef]

have a look here mate:
http://www.airgunbbs.com/showthread....-my-22mm-setup

Thanx

I just went, read it all and asked the first stupid question

[Shed tuner]

No, keep the stroke much as is.. longer will be more efficient.

The point of sleeving is you can reduce the spring stiffness / strength, so making it easier to cock, which is one of the weaknesses, and the small tube increases efficiency.

If you keep stroke around 95mm (estimate), you should get around 13FP and very easy cocking, nice/fast firing cycle. My 22mm convs are running around 88mm stroke, and make 11.5 easy.

[NickG]

No, keep the stroke much as is.. longer will be more efficient.

The point of sleeving is you can reduce the spring stiffness / strength, so making it easier to cock, which is one of the weaknesses, and the small tube increases efficiency.

If you keep stroke around 95mm (estimate), you should get around 13FP and very easy cocking, nice/fast firing cycle. My 22mm convs are running around 88mm stroke, and make 11.5 easy.

Got my 23mm at 90mm, (nice cycle, not earth shattering) reasonable cocking, agree would be good in a PS, but the TX can be better at 25mm.

[NickG]

Hehehehe

Planning a sleeve down to 23mm with a Tx, my PS is holy and you don't touch it!
But a short stroke piston is on it's way.
Was a little tricky to design, you want exactly 13mm longer, but you must make the piston 13mm longer in the PS too
otherwise you beartrap stops working.
Now with the HW type seal the front is longer and there is a millimeter or two of seal material in front, that the standard PS doesn't have.
So your measurement must be from the front, with the seal on, to where it latches on the latching rod, not to the end.
That must be 13mm longer.

Anyone else have ideas?
Input?

I will probably not sleeve it down but make a new comp tube from silver steel.
Have it case hardened, chromed and honed properly.

you wont be case hardening silver steel.

[prosport.177]

The only way i managed to remove the end plug on the pro sport was to remove the 3 delrin buttons. These are machined drilled through the comp tube into the end plug. The hole is about 8/10mm in total depth. When the delrin buttons are made they are pushed into hole, this is all done when the comp tube end plug is screwed in tight.
The buttons then act as locking pins and the threaded end can not be unscrewed, until the buttons are removed.
Bruce i ran into problems when i shortened a ps end plug with lost volume. Thiis was caused by the machined holes being to close to the o ring in the plug. It only left a thread and i could not get it to seal as air was leaking into the 3 machined holes for the buttons.
Hope this makes sense.
These were my findings on the ps tube i took apart.

[brucegill]

The only way i managed to remove the end plug on the pro sport was to remove the 3 delrin buttons. These are machined drilled through the comp tube into the end plug. The hole is about 8/10mm in total depth. When the delrin buttons are made they are pushed into hole, this is all done when the comp tube end plug is screwed in tight.
The buttons then act as locking pins and the threaded end can not be unscrewed, until the buttons are removed.
Bruce i ran into problems when i shortened a ps end plug with lost volume. Thiis was caused by the machined holes being to close to the o ring in the plug. It only left a thread and i could not get it to seal as air was leaking into the 3 machined holes for the buttons.
Hope this makes sense.
These were my findings on the ps tube i took apart.

Thanks Charlie. I had no idea the delrin buttons go all the way into the end plug! (sorry for the miss information above!). Cheers for the info.... TX is looking more appealing but I've had bloody loads of them now.

[Kuberboef]

Hi all

So me and a mate took apart the PS comp tube today.
And looks like the o-ring was faulty.
Finding that o-ring this side of the pond was just to much, so we simply machined
the plg slightly to take a slightly different o-ring.
Put it all together again, those "plastic" pins were a little of a challenge but was dealt with.

A little lube on the seal and all went in!
Power went from around 760fps down to 740fps, JSB 8.44gr 4.52mm

I just don't understand!