I do my best to measure shoulder bump, trying to get it to 1-to-2 thousandths just like everyone else, but doing that using calipers and comparators makes that very tough. Measuring to the thousandth on these tools is "iffy" at best, and for some reason usually impossible for me. I saw this gadget mentioned in another post, and since I already have the Wilson Case Gauges for the four calibers I reload ... I decided to give it a try. Everything else I've gotten from L.E. Wilson has been useful, helpful, and machined to a very high quality, so I figured this was a good bet.
All I can say is "Wow!" ... this gadget works really well, and makes shoulder bumping so much easier and more accurate. Now if you don't have the Wilson Case Gauges, this is a useless tool, but if you do, it allows super-precise measurement right down to the thousandth, and it's repeatable and predictable without all the gyrations that make comparators so tough to use in these very small measurement increments.
I give this gadget two thumbs up for both ease of use and precision machining ...
All I can say is "Wow!" ... this gadget works really well, and makes shoulder bumping so much easier and more accurate. Now if you don't have the Wilson Case Gauges, this is a useless tool, but if you do, it allows super-precise measurement right down to the thousandth, and it's repeatable and predictable without all the gyrations that make comparators so tough to use in these very small measurement increments.
- Measure a fired but unsized case per the instructions.
- Size and bump "very" lightly ... since you can always bump more, but not less.
- Measure the sized case and do the subtraction to get your precise bump.
- Adjust your die or shell-holder until you get the bump you're looking for.
I give this gadget two thumbs up for both ease of use and precision machining ...