Vulcan --------- Cylinder 27mm X 79mm - transfer port 2.5mm X 19mm
Webley Hawk --- Cylinder 25mm X 79mm - transfer port 4mm X 16mm
Westlake B2 ---- Cylinder 25.4mm X 80mm - transfer port 4mm X 28mm
All the best Mick
PS:- notice how I managed to slip a B2 in there Tone --- Bruce may never notice if we keep quiet