I have a large number of cartridges at a historic mine site in southern New Mexico.  The primary occupation of the site is from around 1903 to 1911.  These cartridges are of a very wide variety of calibers.  they were all identifiable  30-30, 30-06, 44-70, 45, etc.  The question concerns their treatment.  Virtually every one of them was found crimped in almost exactly the same place on the cartidge.  Anyone have any idea what this behavior is?