Ammunition and explosive-charge making – Ammunition making – Caps and cartridges
Reexamination Certificate
2001-10-17
2002-11-26
Jordan, Charles T. (Department: 3644)
Ammunition and explosive-charge making
Ammunition making
Caps and cartridges
C086S019500, C086S023000
Reexamination Certificate
active
06484616
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to devices used to manufacture or assemble firearm ammunition using either new or used metallic cartridge cases. Specifically, this invention combines the necessary means to trim cartridge cases to a predetermined length while removing burrs and chambering both the inside and outside of the case mouth, remove cartridge case material used to crimp primers into the cartridge case by swaging, cutting the cartridge case primer pocket to a predetermined depth, chambering both the inside and outside surface of the cartridge case flash hole, and trimming the wall thickness of the cartridge case neck to a uniform dimension, all with the same device and by a manner that increases convenience and accuracy over any other means currently available.
Description of Prior Art
Numerous machines have been invented to perform the necessary steps to recondition and reuse fired cartridge cases. During the physical act of firing a modern firearm using metallic cartridge cases, the case expands slightly due to the high pressure contained inside the cartridge case. The case is contained on all but one surface by the firearm's chamber so that the projectile is forced to leave the cartridge case and travel through the barrel to the muzzle and towards its intended target by the intense pressure released or generated by the propellant. Once the firing process has concluded, the now empty cartridge case may be removed from the firearm and either discarded or reused.
It is standard accepted practice to resize or swage the cartridge case into a metallic die to reform the case to its proper dimensions, which were distorted by the high pressures generated during the previous firing. When the cartridge case is resized, the diameters of the case are reduced slightly so the case may then be reinserted into a firearm's chamber without interference. Without resizing, the cartridge case may not enter a chamber and function as intended. While the resizing process reduces the diameters of the case along its main axis, the material displaced lengths the cartridge case along the major axis of the case. Typical values of overall length increase range from 0.002″ to 0.015″ per firing and resizing sequence. When using the existing known art to resize a cartridge case, the additional length appears at the mouth of cartridge case. It is then necessary to remove the excess material before reusing the case.
To remove this excess material from the cartridge case mouth, some type of mechanical process is used to cut the material off of the cartridge case while leaving the head of the case undisturbed. Typical devices currently used include the use of a rotating cutter(s) acting on a fixed case held by the case head, rotating cutter(s) acting on a fixed case held by some type of gage or die, rotating cutter(s) acting on a case inserted into some type of fixed gage or die, or files used to remove the case material exposed above a gage surface. These devices all leave the cartridge case mouth in full contact with the cutting device until manually removed. Most of these current devices also leave burrs along the freshly cut surface of the case mouth, which must be removed to safely reuse the cartridge case. If the burrs are not removed from both the inside surface and outside surface of the case neck before a projectile is inserted in the cartridge case, then into a firearm's chamber, excessive force may be applied to the projectile by the chamber walls acting like a clamp or collet holding device restricting its ability to leave the cartridge case and cause increased pressures inside the firearm chamber.
While many devices exist to trim the excess material from a resized metallic cartridge case, none are known to index the cartridge case to the cutting surfaces and remove the case from the cutting surface automatically or prevent the case from contacting the cutting surface without some action, namely physically moving the cutter and case away from each other.
Accordingly it is an object of this invention to trim the mouth of resized cartridge cases to the desired overall length by indexing the case off some known repeatable point of the case other than the case head, chamber the case mouth edges on both the inside and outside and outside surfaces, and automatically withdraw the case from the cutting blade when additional manual force is not applied. The cutting of material from the case neck stops when the cartridge case has engaged the case holder assembly and the moving portion of the case holder assembly reaches a mechanical stop. Withdrawing the case from the cutting surface occurs when the manual pressure applied to the case during the trimming process is removed. A spring device lifts the cartridge case away from the cutting surface until the user applies some pressure to the case to force the case towards the cutting surface, and away from the cutting surface once the user added pressure is removed.
To reuse cartridge cases that have had the primer swaged or staked in place, it is necessary to first remove the used primer and recondition the primer pocket to remove the material displaced by the swaging process. Without removing this material, a new cartridge primer cannot be inserted properly because the exposed edge of the primer pocket is dimensionally smaller than the remaining depth of the pocket and the outside diameter of a new primer. Existing devices used for this process are typically one of two types, those cutting material from the case, and those that swage the material back away from the cartridge case primer pocket using a mechanical force. With either device it is desirable, for more accurate ammunition, to make the finished primer pocket as uniform in dimension as possible and with a flat bottom in the primer pocket perpendicular to the cartridge case main axis. By using a mechanical cutting device to remove the displaced material away from the primer pocket and cut the bottom of the primer pocket flat, the overall dimensional accuracy of the finished primer pocket is higher than with a swaging type device. The overall dimensional uniformity from case to case in a given lot of cartridges will greatly influence the accuracy potential of the cartridges when fired. Ammunition prepared with cartridge cases using uniformed primer pockets will be generally yield a smaller dispersion around an aiming point, a very desirable feature for users trying to achieve the utmost in accuracy.
Other devices exist for removing the excess material and cutting the bottom surface of the primer pocket, but typically are two step devices. One step is to remove the excess material, and another to cut the flat surface of the pocket. One other device is known to exist the combines these two steps into one process. While there are several known tools to remove the excess material and uniform the bottom of the primer pocket, none are known to be combined with a cartridge case trimmer that automatically removes the case from the cutting surface.
To facilitate more uniform ignition of propellant inside a cartridge case typically yields a more accurate cartridge. Accordingly, it is common practice to remove any burrs present around the opening inside a cartridge case between the primer pocket and the inside of the cartridge. This passage is typically known as the flash hole. If burrs are present on either side of the flash hole, the flame released from the primer upon detonation may not enter the cartridge case main body to ignite the propellant in an even manner. Propellant ignited from an even axially centered flash produces more uniform ignition and combustion than that ignited by a flash entering the cartridge case main body in some random orientation. As is seen with uniforming primer pockets, ammunition prepared with cartridge cases having the flash hole surfaces deburred will typically yield a smaller dispersion than those without the benefit of the deburring process. Typically known devices for deburring the flash hole of cartridge cases use a small me
Brown Kurt J.
Hayes Bret
Jordan Charles T.
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