Help with a FWB model 2 (unable to fill)

[Model2]

I've recently picked up a fwb model 2 and I'm having an issue with filling it. I have read the previous thread I've found on here (http://www.targettalk.org/viewtopic.php?t=16632) but the issue I have is different.

In order to fill it I:
1. Put the cylinder in the freezer for 30 minutes
2. Used the bleed cap to bleed off the last ~10g of CO2 from the cylinder
3. Attached the fill adapter to my supply cylinder
4. Attached the (cooled) pistol's cylinder to the fill adapter
5. Opened the valve on the supply cylinder

However at this point CO2 started coming out of the side of the fill adapter (through the hole pictured). I turned off the supply cylinder and disconnected everything. The pistol's cylinder obviously was not properly filled and contained approximately 15g of CO2. At this point I had a look at my fill adapter comparing it to pictures online and the exploded diagram; it looks like there is meant to be a screw in the side of the fill adapter that I might be missing. It's listed on the exploded diagram as part 1830.002.1 "Filling adapter srew" [sic] and can be seen in the pictures in the above mentioned thread. However to add to my confusion I've seen listed online fill adaptors for sale that appear to be missing this screw in their picture. Finally my fill adapter does not have any thread in this hole that the screw might or might not belong in.

I've attached pictures of the parts below so that you can see what I'm talking about.

What does this screw do? Is missing it the root cause of my inability to fill my cylinder and the CO2 the streamed out the side of the fill adapter? Or is there something else missing such as an o ring?

Thanks for helping,
Angus

The outside of the fill adapter and one of my cylinders

Inside of the fill adaptor

The other side (supply tank facing)

[j-team]

Are you tightening the cylinder to the adaptor with a wrench? Hand tight will not be enough for these (hand tight on the pistol is OK, but not on the filling adaptor). They seal end on so the hole in the side should not be a problem, it's there to vent the small amount of gas that releases as you remove the filled cylinder. Also, the seal in the adaptor is probably no longer any good (probably gone hard with age) try a new one of these (it's the white part with the sintered filter in the middle).

[zztop]

I have a Mod 2 and I only need to hand tighten to fill the cylinder. I don't think that is the problem. If you have a look at "inside.jpeg", maybe blow it up a bit, you can see radial cracks in the nylon type sealing washer. It is supposed to be a face seal and CO2 is able to leak out along those cracks. It follows the thread for a short time then exits via the relief port (the hole in the side) exactly as it should. So the simple fix is to replace that washer, while your at it you may as well replace the donor bottle side seal as well. I think that if you over-tighten the small cylinder on to the adapter, that may contribute to damaging the seal. I imagine when they are new they are reasonably soft to aid sealing.
Sorry, do not know where you buy these from...............
edit; and if you remove the cylinder from the pistol and have a look where it screws in you will probably see another one of those seals, get 3

[Model2]

I was only tightening it by hand as the manual didn't specify and I didn't want to damage the thread. I will try to see if it fixes the problem temporarily and contact the importer about replacement seals.

Thanks for your help.