Hardwood dowel or brass punch + light hammer to barely tap front sight, then retighten. The other issue is common, you have to pull out on the elev knob with the screw loose, rotate knob, hold sight aperture down with thumb of other hand. Unlikely you'll ever get it perfect b/c, among other things, different ammos will print slightly different elevations at 200, 300, 600. So write down your tactile/audible clicks from dead bottom up to 100 or 200 yard line and incrementally from there to 300 and 600, memorize them, consider them your sighter zeros. For most shooters the 200 yd zero is the indispensable one (you can do it on a smallbore target at 25 yds if you have to). Model airplane paint or nail polish will give you index marks you can see. Good luck.