I got a Hawke 4-12x40 AO for my new Air Arms TX200 from Pyramyd yesterday and I find the adjustable objective is very difficult to turn. I have to literally take my whole right hand to turn it. Its even more difficult with my left hand - arthritic thumb joint. I'm assuming it will get a bit easier with use - but, how much easier. I don't know if there's anything to be done about this. Any suggestions?