Quote Originally Posted by tinbum View Post
If anyone (Alistair?) has some measurements written down I could do with the length of the UK spec spring. This ones a 2.8mm wire 12.5mm ID 23 coil 155mm long.
These are some measurements off a HW30 spring from the official HW importer here in Norway(they only do the full power stuff):

ID:12,2mm
Number of coils: 28
Wire diameter: 2,8mm

I did a "max power setup" on dads old HW30mII, the type with the "perfekt" trigger some while ago. The above spring, with a Vortek seal was pushing 7.3grs JSB's at 680fps, thats around 7.5fpe. The gun felt a bit "snappy", but accuracy was great. It has the same spring now, but a bit softer seal that slows things down a bit, and the tophat removed for less spacing. Much more pleasant to shoot that way.