Ammunition and explosive-charge making – Ammunition making – Caps and cartridges
Reexamination Certificate
2000-05-11
2002-06-04
Tudor, Harold J. (Department: 3641)
Ammunition and explosive-charge making
Ammunition making
Caps and cartridges
C086S023000, C086S024000, C086S028000, C086S037000
Reexamination Certificate
active
06397718
ABSTRACT:
BACKGROUND OF THE INVENTION
The key to accurate ammunition is concentricity and uniformity in every respect. Cartridge cases received directly from a manufacturer typically bear non-uniformities and eccentricities from piece to piece that can affect the potential accuracy of the ammunition. Competitive marksmen usually rework each cartridge case in order to produce ammunition with greater concentricity and uniformity and hence the potential for improved accuracy.
A typical prior art cartridge case
10
is shown in
FIG. 7. A
bullet (not shown) is held in place by the cartridge neck
14
(terminating in a mouth
15
) of the cartridge case
10
. An extractor groove
19
circumscribes the cartridge case
10
near its bottom. A primer pocket
18
contains a primer, which ignites when struck by the firing pin of the gun being used. A flash hole
20
connects the primer pocket
18
with the propellant chamber
22
, so that the ignited primer will ignite the propellant contained in chamber
22
thereby forcing the bullet (not shown) out of the neck
14
.
Among the non-uniformities typically present from one cartridge case
10
to another cartridge case
10
is the size and shape of the flash hole
20
, which is sometimes partially occluded by burrs extending from the inner perimeter of the flash hole
20
. Even a small difference between flash holes
20
can affect the ignition, chamber pressure, and velocity uniformity, which in turn affect the uniformity and accuracy of the ammunition. Moreover, any non-uniformity between primer pockets
18
will affect the propellant ignition uniformity by altering the contact of the primer with the bottom of the primer pocket, thereby changing the firmness of primer seating and the firing pin-to-primer relationship, which in turn affects ignition characteristics and ammunition uniformity.
Non-uniformities in the form of wall thickness variations at the neck
14
and the mouth
15
of the cartridge case also affect the neck/bullet/rifle chamber concentricity, bullet alignment in the bore of the firearm, and accuracy of the ammunition. Any variation in the thickness of different portions of the circumference of the neck may cause the bullet to be held in misalignment with a firearm's bore, forcing the bullet into an imperfect shape under chamber pressure when fired. Non-uniformities and eccentricities of this type from cartridge case to cartridge case cause accuracy to deteriorate.
SUMMARY
In a first separate aspect, the present invention comprises a device for machining a cartridge case that has a neck comprising a circular neck wall, a mouth and a primer pocket. The device comprises a gripping assembly, adapted to accept and retain a cartridge case and a neck machining assembly, positioned to engage the cartridge case from a first direction and adapted to machine the neck of the cartridge case. Additionally, a primer pocket machining assembly is positioned to engage the cartridge case from a second direction, opposed to the first direction, thereby permitting simultaneous primer pocket and neck engagement, and adapted to machine the primer pocket.
In a second separate aspect, the present invention is a device for machining a cartridge case that has a neck, a mouth and a primer pocket. The device comprises a gripping assembly, adapted to accept and retain a cartridge case and a neck machining assembly, adapted to machine the neck of the cartridge case. In addition, a mouth machining assembly has a fixed positional relationship to the neck machining assembly so that the mouth machining assembly engages and machines the mouth of the cartridge simultaneously to the machining of the neck of the cartridge case by the neck machining assembly.
The foregoing and other objectives, features and advantages of the invention will be more readily understood upon consideration of the following detailed description of the invention, taken in conjunction with the accompanying drawings.
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Elder Bradley R.
Jamison John R.
Jamison John R.
Law Office of Timothy E. Siegel
Siegel Timothy E.
Tudor Harold J.
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