I have the same problem with my HW110, 11.14ftlb with .177, JSB Exact 4.52 and 10.99ftlb with JSB Exact heavies 4.52 very odd. I have tried 4.51 and they are even lower. I would like it doing 11.7ftlb with JSB Exact heavies which equates to around 715fps as I also only hunt. Is it only Hull Cartridge that can work on these due to their construction? Although I have been shooting air rifles for 40 years I have no experience of dismantling PCPs.
Cheers, Phil
THE BRAIN CANNOT ASSIMILATE WHAT THE POSTERIA CANNOT TOLERATE