An example of an undercut front sight would be the one on a Ruger Target 22 Auto. While a good idea for target work, extreme examples will "eat up" your holster while accumulating globs of leather, etc. Various custom pistolsmiths sell what they consider to be the ultimate front sight and often offer explanations. I've heard that a previous poster, Ken ONeill, produces a really good one. You have to consider if the pistol is going to be carried in a holster and choose accordingly.
Personally, I'd go with a finely serrated Patridge or Improved Ramp front blade and the BOWEN Target adjustable rear sight. The BOWEN gives a sight picture similar to the BOMAR rear sight that was THE sight for IPSC and target shooters prior to all the optical types. There is a BOWEN on my favorite stainless Super Black Hawk, but I didn't replace the factory front. I wish I had gotten something different--and better now. Jim Stroh (ALPHA PRECISION) did his usual excellent job on "blue printing" the Ruger after about 15-to-20,000 rounds and it will do considerably better than I can shoot it.
Mr. Stroh is going to be doing some work for me, on my 44 Accu Sport among others. You have reminded me that a BOWEN sight and appropriate front blade replacement would be money well spent. If you don't have it, consider buying Hamilton Bowen's book, THE CUSTOM REVOLVER. You will find it an education and well worth the $40+; and he will sign them--another plus.
