So this is my first post on this forum,

I have a HW90k .177, bought new by me just over a year ago, when I got it, it was making just under 11ftlbs but has decreased gradually in power to under 9ftlb.

I decided to get the parts I needed, seals and pump and set about stripping and rebuilding it, so got the gun apart, cleaned and relubed all the parts, the inertia weight was siezed so I freed that up,replaced o rings and applied silicon grease to them, I put about 5ml of oil and gearbox additive in the ram as people had advised, I polished the outside of the piston pumped it up to 11.3ftlbs and went to the range, the gun was leaking air and oil from the ram after every shot and power dropped down to 8 ish ft lbs again.

Stripped the gun again and couldn't see anything wrong with the o rings I had replaced but the leak was definitely coming from where the o rings seal the ram, could I have put to much oil in the ram or does anyone know why this could be happening?

Any help would be greatly appreciated.