Plenty on the bay, and B&Q sell brass tubing in their metal rack, got some there to use on a Crosman revolver.
Baz
BE AN INDEPENDENT THINKER, DON'T FOLLOW THE CROWD
If this is all for your Hawk MK3, Alistair?
The using a Vulcan breach seal allows you to sleeve the transfer port right through from the cylinder face to the breach face --- I only mention this as the Hawk breach seals used to be different to the Vulcans.
All the best Mick