Took my new 9mm Kimber Stainless Target II 1911 to the range today to sight it in. Could not move the rear sight screw up!

I managed to turn it down 2 clickes but then it stopped moving nor would it go back up again. Rather than force it and possibly burr the screw head (I only had small screwdriver with me in my kit) I returned home and googled the problem. That's when I learnt of the set screw on the right side of the sight (I thought it had something to do with preventing the sights moving sideways in the dovetail).

I found a hex key to fit (the smallest one I could find) and even after removing the set screw entirely the elevation adjusting screw would not budge until I got the largest screwdriver that fit the slot and gave it steady pressure for a few seconds which loosened it up, after which the adjustment screw started to move freely.

Wonder why the owners manual does not say to loosen the set screw before trying to turn the adjustment screw?