DON'T USE THE CASE HOLDERS!
Using this cutter as instructed will likely produce off-centered chamfering of the case mouth; too much on one side, little to none on the opposite side. This is because the diameter of the bearing (the part of the trimmer tool that holds the rotating cutter shaft) is usually not equal to the diameter of the shell holder, so the cutter isn't centered on the case mouth. The diameter of my bearing is 0.998". I own seven shell holder's and their diameters are: 0.996", 0.997", 0.997", 0.9975", 0.9975", 0.9975", and 0.998" (this last one actually works). I spoke with a Technician at Wilson and he said they can't guarantee consistent diameters for their shell holders because they start with 1" stock and polish them all down by hand, so the resulting diameters are random. Well that works if you're just length trimming, but if you're chamfering they all have to be exactly the same diameter as the bearing. I went back to using my old Hand-Held Chamfering Tool, and soon realized that the reason it works is because it is allowed to self center. So I returned to the Wilson Trimmer Tool, but this time I didn't use a case holder. I just held the case head against the adjustable screw stop using my index finger and thumb, inserted the cutter head into the case mouth, and allowed the case mouth to self-center on the cutter while I turned the crank handle with my other hand. It worked GREAT! I quickly ran 100 cases through and they all had perfectly centered chamfers, all at exactly the same depths! So I figured I'd post what I learned. Maybe this work-around will work for you too. Also, I had my gun smith blue all the parts, as I read that they rust easily.
