Cartridge case trimmers, as contemplated herein, are of the mini-lathe variety, i.e. a selected cartridge case is locked in place and a blade is mounted on, or is an integral part of, a rotating shaft that is designed for controlled movement toward the mouth of the cartridge to engage and trim the case back to a desired length. Trimmers such as described above are used for refurbishing cartridge cases, i.e. where the cartridge has been fired and the spent cartridge case is cleaned, reshaped and reloaded. Such reloading of cartridge cases is popular among users of large numbers of cartridges, e.g., hunters, target shooters etc. There is a substantial savings to the reloader and he can, in effect, customize his own cartridges.
The trimming operation is made necessary because the explosion that takes place in the cartridge causes some expansion and elongation of the material of the cartridge case. The cartridges are designed to precisely fit the chamber of a specific type of firearm and thus the need for the trimmer.
The problem that is addressed by the present invention concerns the necessity of trimming cartridge cases to different lengths, i.e., different caliber cartridges (for different firearms) have different lengths. The enthusiast who loads his own cartridges is very likely to have a number of firearms and thus a number of different caliber cartridge cases that must be accommodated by the trimmer.
The trimmers presently in common use are equipped with an adjustable stop member that can be set so that the movement of the cutter into the cartridge case mouth is stopped at precisely the desired length of the cartridge. However, every time a different cartridge is to be trimmed, the reloader must readjust the stop member. Readjustment is a time consuming and tedious trial and error process.