Does not work correctly on all cases
Used in conjunction with an L.E. Wilson Case Gage this becomes an excellent and easy to use tool for knowing the headspace of a case. The micrometer does not have a vernier scale, but most users will probably be able to determine variations in headspace within +/- 0.0002". The result: shoulder bumping is no longer a guessing game. However, there is one caution. As shipped, the micrometer spindle has a considerable chamfer, so much so, that the spindle head can drop into the primer pocket recess of some cases (I ran into this problem with Lapua 8x57 Mauser cases). I sent mine back to L.E. Wilson and much to their credit they removed the chamfer from the spindle at no cost. Now it works fine. FYI: the spindle diameter is close to 0.270". If any part of a primer recess has a diameter greater than 0.270" then removing the chamfer on the spindle will not solve the problem. I regret that I did not record the diameter of the "as shipped" flat portion of a chamfered spindle, As a consequence, I can not tell you the maximum diameter of a primer recess for which the "as shipped" micrometer will give you reliable readings, but I suspect it will be reliable on most cases.
