BSA Mercury

[Weasle]

After 50 odd years of being a confirmed air rifle nut...I have never taken a Mercury apart.
This one is from the early '70's and never been apart...I know the original owner who bought it new in 1972.
How much pre-load should I expect when unscrewing the trigger block....which is now....at last and with assistance free and revolving/unscrewing nicely.

BTW its sees to be suffering from a perished seal and buffer washer as it sticks quite horribly when trying to cock it.


Many thanks in advance from the learned members.

Cheers Steve