I have been working on the same sighting problem with a Uberti Walker over the winter. I went the route of filing down the hammer to lower the POA. I now have it shooting POA @ 75 yrds or thereabouts. To do this required taking the top of the hammer down below where the bottom of the original notch was. With a hammer flat across the top I figured out the windage, marked that point on the hammer (mine was shooting right so I had to go left of center a bit), then I filed down a nice smooth and wider than the original, notch. I figure I took 2mm off of the top of the hammer during this process. No problems with the funciton of the gun whatever. Now that I got the sighting taken care of, the next puzzle is figuring out which load is the most accurate. To date the 50 grain loads are winning the contest but, these hotter loads appear to lead up the barrel after about 15 shots and accuracy begins to suffer, meaning a few minutes scrubbing the barrel with a brush before resuming shooting. I would like to find a lower grain charge that offers good accuracy and which doesn't use 4 Wonder Wads a chamber to fill the void. I have tried wheat germ as filler, not happy with that, anyone have any suggests?