I've never had any recoil effect on my HW100, I just thought PCPs suffered a little muzzle flip & that's it. Fair enough my HW100 is running at legal limit velocity but if this is the case, surely there would have been some effect. If your rifle is running at getting on rimfire velocity like an FAC Career 707 (80 ft/lbs) then that could be plausible. Still, stranger things have happened. Having said that, if your HW100 is running at FAC velocities, the muzzle flip would be much harsher & the effect of the muzzle rising when the pellet exits the barrel, could give the illusion of recoil. I'd still like to know how that works out though, I love anything technical.