the tightness is due to the rubber o-rings on the turret rubbing against the little skirt housing they fit into. You can either try to 'grease' the o-rings, or get one size smaller/thinner to relieve some of the pressure they are causing.
You'll see what I mean if you remove one of the turrets, slip the o-ring off, reinstall the turret and spin it ... no resistance other than the ball & detent mechanism that holds the 'clicks' ...
