To adjust, I believe you should first rotate the large knob on the right side of the rib to the detent that achieves the lowest setting of the sight slide itself. I can't remember how the rear sight allen screws are marked on top. It may be "7", "15", and "25", or "1", "2", "3". The thumbscrew should have corresponding marks. Regardless how the sight is marked, you have three distances you can pre-set for your ammo and desired hold on the target.

With the knob at the "1" detent, (lowest) adjust the allen screw marked "1" to the correct POA at that range. Then, move back to the 15 yard line, (or whatever distance desired) move the large thumbscrew/dial to the middle detent, (2) and after shooting the desired hold on the target, adjust the allen screw marked "2" to the correct POA at that range. Move back to the 25 yard line (or whatever) and turn the large thumbscrew so that the sight body is at it's highest setting (3) ....then, shoot the gun and adjust the last allen screw (3) to the correct blade hight for that distance. You can then change the sight height for the distance you are shooting by simply rotating the large thumbscrew to the desired setting.....1,2, or 3.

This allows PPC shooters to use the "hold" they want at different distances....and they don't have to carry a screwdriver and make click sight adjustments between stages.

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Ret. LE, FA Instr, S&W Armorer