Oh right, sorry could you explain a little more lump mate, im looking in the manual but cant see return resistance...
EDIT:
In the manaul there are three screws you can adjust -
1 - controls triggers length of pull
2 - controls how far the trigger will travel after it reaches the firing point
3 - controls trigger tension
I have adjusted all of them but to no avail, there only seems to be a tiny margin to which 1 and 2 can be adjusted before they either
A - stop the trigger moving
B - start to stick out of the frame