Here's a PPC Model 10 and a 6 inch 686 that I used a bit for IHMSA:




The Aristocrat rib mentioned above has three settings, plus the "regular sight adjustments. But it's all on the back end.

And a semi-retired silhouette revolver:



In actual fact I liked my adjustable front sight 29-5 more for Field Pistol class. I found a range that still shoots IHMSA matches. Might have to jump back in. Great "instant gratification" game played at "silly" distances and less than warp speed. As long as you don't mind the misses it's great fun!