The case trimmer should trim the case somewhere between the max. and min. allowable case length for the cartridge in question. Our case length gauges have a tolerance of +.000 and -.015. Handgun cartridges that headspace on the case mouth have a tolerance of +.000 and -.010. It works much like a "go-no go" gauge in that if it does not trim, the case did not need it.
If yours has a length that falls outside of the minimum and maximum allowable length, it should be returned to the factory for a replacement.
Our address is:
Lee Precision, Inc.
4275 Highway "U"
Hartford, WI 53027
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