Checkout this text of one of the Jamison patents
United States Patent 5,826,361
Jamison October 27, 1998
Short-action chamber and bolt assembly for high power firearm cartridge
Abstract
A firearm cartridge case capable of withstanding internal gas pressures of at least about 50,000 psi has two substantially cylindrical portions of significantly different diameters interconnected by a frusto-conical shoulder portion. The case has a ratio of its overall length to its diameter, at a location 1.25 inch from its base, of no more than about 4.2, giving it an unusually short, fat profile. The base of the case has a rim with an outer diameter substantially no less than the case diameter at the aforementioned location, to facilitate reliable feeding of the cartridge from the magazine. The corresponding firearm chamber which matingly accepts the cartridge is capable of withstanding internal gas pressures of at least about 65,000 psi. A short-action bolt assembly smoothly and reliably feeds and chambers each cartridge by providing an extractor grippingly engageable with the cartridge by movement of the cartridge transversely to the bolt face when the bolt is in its unlocked position, so as to grip the cartridge while the bolt pushes the cartridge into the chamber.
Inventors: Jamison; John R. (84784 Christensen Rd., Eugene, OR 97405)
Appl. No.: 818440
Filed: March 17, 1997
Current U.S. Class: 42/25; 42/16
Intern'l Class: F41A 003/00
Field of Search:
Looks to me like the Winchester/Browning Patent Attorneys goofed.
HBB
Last edited by hillbillybear; 12/27/05.
