So I've owned an old HW77K for a few Years, I think its about 1987 1041***K ?

I've never taken it apart , it does look very original and as dry as a bone in the breach.

It shoots ok, makes reasonable power but feels dry under cocking, and makes that awful boing sound when fired.

I've purchased some bits from Knibbs and plan to have a go at improving the old girl.

Could anyone share an opinion on the following parts , have I made the right purchases ?

Titan XS No 9 mainspring.
Titan XL guide
Titan top hat
Titan power boosters
HW77 breach seal
HW77 piston seal

And some molybdenum grease.

This will be my first attempt to improve a spring rifle.

Thanks for any comments and tips !