Post your C.B.O.L.

[Mad Charlie]

I purchased the tap to drill and tap my own cases for this exact reason, a ?modified case? over the counter is not precisely the same neck and shoulder that your loads are. I deprime and size a case drill and tap the primer pocket. I then split the neck and the first bend transition of the shoulder smooth the cut inside and out with a jewelers file and walla the hornady overall length gauge is ready. By buying the tap I can use this method on every rifle I load for.

The modified Hornady case is not likely to be the same as a case fired and sized for your chamber, but it is easy enough to measure the difference and do the math.

As far as drilling and tapping your own case, the big problem is holding the case without damaging and/or distorting it and keeping it centered. Easy to do if you have the tools.