One of my HW55 rifles had been "improved" inside by a previous owner, so I bought a piston head set from Chamberlains that included a new leather washer, spacer and screw - I much prefer this to a synthetic washer on an older rifle.
I then discarded the "over-powered" spring that had been fitted and replaced it with a new HW55 spring of the type originally specified for this superb little target rifle.....and now it shoots like a dream!
Super smooth and super accurate - just the way they should be.
Rossendale Target Shooting Club. Every Tuesday and Thursday evening 7 - 10pm.