Exactly my situation with the Williams Firesights too, MrBlackCat. I had the rear sight all the way down, and still was shooting high at 25 yards. I called Dawson Precison, explained the situation, and he told me his formula for finding the correct height for the front sight. I gave him my measurements, and my credit card number, and he made me the correct front sight. I installed it as soon as i got it, went to the range and actually had to come up about 4 clicks to get it dead on at 25 yards. The Williams rear sight worked perfect with the Dawson front sight. But, as I said in a previous post, I put a scope on it soon after. My 74 year old eyes work much better with an optic.