Converted my FWB 601 and made my own shortened loading catch lever as the originals are very hard to find. Raised the scope mounts to fit a 3-9 x40 scope, not the best of scopes but does the job really well. Went to test in the garden on my little range and found i had parallax problems with the crosshair moving all over the place even worse on a rifle which you know can put the same pellet in the same hole over and over again, bit like cheating. I also had a problem with the scope not focusing on x9, just a blur, but Ok on x3. Being a non AO scope i wondered if anything could be done apart from getting the correct eye relief which i already have, until i watched this video https://youtu.be/T97GCZqbZio so i thought i would give it a go seeing as it a cheap scope, so if something went wrong it wouldn't be a problem. Checked that the end cap on mine could screw off and set magnification to x9 and adjusted it out slowly rather than in until the x9 was fully focussed which to my delight the parallax was gone. I think this scope was set for a firearms distance rather than my 10 metres i normally use. So after a couple of test shots i can now actually shoot the wings of flys, its a bit like cheating, an even more plus that i have silence the FWB with a plug which i thought may have been part of the problem but not. I also done this to a old boxed scope of the same spec which i put away as it as giving me the same problems years ago and now that scope is putting pellets in the same hole. I wondered if anyone has tried this before.