WO2007134855A1 - Douilles de munition a percussion annulaire - Google Patents

Douilles de munition a percussion annulaire Download PDF

Info

Publication number
WO2007134855A1
WO2007134855A1 PCT/EP2007/004584 EP2007004584W WO2007134855A1 WO 2007134855 A1 WO2007134855 A1 WO 2007134855A1 EP 2007004584 W EP2007004584 W EP 2007004584W WO 2007134855 A1 WO2007134855 A1 WO 2007134855A1
Authority
WO
WIPO (PCT)
Prior art keywords
cartridge
cartridge case
cylindrical wall
steel
brass
Prior art date
Application number
PCT/EP2007/004584
Other languages
English (en)
Inventor
John Antony Gamble
Géza Tamás NAGY
Original Assignee
Thomas Steel Strip Corporation
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Thomas Steel Strip Corporation filed Critical Thomas Steel Strip Corporation
Publication of WO2007134855A1 publication Critical patent/WO2007134855A1/fr

Links

Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F42—AMMUNITION; BLASTING
    • F42B—EXPLOSIVE CHARGES, e.g. FOR BLASTING, FIREWORKS, AMMUNITION
    • F42B5/00—Cartridge ammunition, e.g. separately-loaded propellant charges
    • F42B5/26—Cartridge cases
    • F42B5/32—Cartridge cases for rim fire
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F42—AMMUNITION; BLASTING
    • F42B—EXPLOSIVE CHARGES, e.g. FOR BLASTING, FIREWORKS, AMMUNITION
    • F42B5/00—Cartridge ammunition, e.g. separately-loaded propellant charges
    • F42B5/26—Cartridge cases
    • F42B5/28—Cartridge cases of metal, i.e. the cartridge-case tube is of metal

Definitions

  • the present invention relates generally to the field of ammunition and more particularly, but not exclusively, to an improved cartridge design.
  • Rimfire ammunition is often used because it is relatively inexpensive as compared to centrefire ammunition.
  • a rimfire cartridge 10 is illustrated in Fig. 1.
  • the cartridge 10 includes a projectile or bullet 12 connected to a cartridge case 14 at crimped portion 17. Opposite projectile 12, the case 14 has a base 16.
  • Case 14 also includes a cylindrical wall 22 having an inner surface 22a and an outer surface 22b. Wall 22 and end member 16 define an interior 24. Extending radially outwardly from wall 22 and extending between wall 22 and base 16 is circumferential bulge 18. Bulge 18 defines an annular pocket 20 communicating with interior 24.
  • a quantity of fluid priming charge 28 is spun into annular pocket 20 and allowed to dry.
  • a propellant-powder charge 26 is then placed within interior 24 of case 14.
  • a firing pin which is configured to strike case 14 at outer rim 18, crushes the priming charge in the annular pocket 20 which in turn ignites the propellant-powder charge 26.
  • the propellant-powder charge 26 burns rapidly and creates gas as it burns. The pressure from the gas forces the projectile 12 from the crimped portions 17 and propeis the projectile 12 down the barrel of the firearm.
  • rimfire cartridges are produced from brass. Apart from being expensive, the brass is difficult to work. During the forming process of the cartridge expensive intermediate annealing treatments are needed to soften the material and make it formable again for further processing. For many years attempts have been made to produce rimfire cases from coated and uncoated steel, however, extraction and manufacturing problems have been problems in this regard. The problem of extraction of shells after firing has been observed from certain firearms, including revolvers.
  • the cartridge should be capable of use in existing firearms with minimum modification to its components whilst retaining excellent extraction properties after firing.
  • the present invention is directed towards meeting these needs, among others.
  • One aspect of the present invention is directed to a rimfire cartridge comprising a cartridge case wherein the cartridge case comprises substantially of steel.
  • a method for making a rimfire cartridge case comprising steel for a firearm is provided.
  • One form of the present invention is directed to a rimfire cartridge
  • a cartridge case having a cylindrical wall and a closed base, the cartridge case having a circumferential bulge at the base extending radially outwardly from the cylindrical wall and having an opening into the interior of the cartridge case; a projectile provided on and closing the cartridge case at an end opposite the base; a propellant-powder charge provided inside the cartridge case; and a priming charge for igniting the propellant-powder charge provided in the circumferential bulge in the cartridge case wherein the cartridge case comprises substantiaiiy of steei.
  • the cartridge case comprises substantiaiiy of steei.
  • at least 70%, at least 80%, at least 90%, at least 95% or 100% by weight, of the cartridge case is made of steel.
  • the extraction properties of the steel cartridge did not match those of the brass equivalent.
  • the cylindrical wall of a brass cartridge was 0.22 mm. It is preferable that the steel cartridge has a wall thickness at half the height of the wall of at most 198 ⁇ m (i.e. 10% thinner than the comparable brass cartridge), preferably of at most 176 ⁇ m (i.e. 20% thinner than the comparable brass cartridge), more preferably of at most 154 ⁇ m (i.e. 30% thinner than the comparable brass cartridge).
  • the weight of the steel cartridge is significantly reduced in comparison to the brass equivalent resulting in lower consumption of material and a lower overall weight of the ammunition. It may also have a cost effect in that most steel types are less expensive than brass.
  • a method for making a rimfire cartridge case for a firearm includes (a) providing a blank, such as a disc, by stamping from a steel sheet, plate or coil; (b) forming the blank into a cup by a drawing operation; (c) forming the cartridge case from the cup by one or more subsequent deep-drawing and/or one or more wall-ironing operations; (d) heading the wall base by forming the circumferential bulge extending radially from the base of the cylindrical wall.
  • the shells may be subjected to an annealing treatment after forming in their entirety, or to a mouth-anneal only where the opening of the cartridge is annealed.
  • the hardness of the steel in the shell wall is below 250 HVO.5, preferably below 225 HVO.5, more preferably between 125 and 200 HVO.5.
  • the ratio between the yield strength and the tensile strength is above 0.75, preferably above 0.80, more preferably above 0.85. This ratio is important because a flat tensile curve means that the hardness or yield strength increase of the wall after forming the cartridge is limited in comparison to the hardness or yield strength of the pre-conversion material.
  • a priming charge for igniting the propellant- powder charge is provided in the circumferential bulge in the cartridge case, for instance by spinning a liquid priming charge and followed by drying. This operation is followed by placing a propellant-powder charge provided inside the cartridge case into the interior of the cartridge case and lastly a projectile is placed into the end of the casing opposite the base and fixed thereto, for instance by a crimping operation.
  • the steel used to produce the cartridge case may be uncoated, but it may also be provided on one or both sides with a coating.
  • the coatings can be functional and / or decorative. This coating may be identical on both sides, but it may also be different, both in composition and dimension.
  • the coatings may be metallic coating, and / or polymer coating and / or composite coating.
  • the metallic coating is preferably selected from the group consisting of copper, nickel, brass, bronze, chromium, zinc, tin, cobalt, aluminium and combinations or alloys thereof, such as nickel-zinc alloy (NiZn).
  • the steel used to produce the cartridge case is a low carbon steel, such as an AiSi 1005, 1006, 1008 or 1010 steel.
  • the carbon content of the steel is at most 0.05% in weight.
  • the carbon content of the steel is at most 0.01%.
  • the preferred range of Mn is between 0.15 and 0.60%, more preferably between 0.20 and 0.40%.
  • the steel used for the cartridge is a clean steel.
  • the so-called clean steel generally is the steel in which the content of impurity elements, such as phosphorus, sulphur, total oxygen, nitrogen, hydrogen and inclusions are very low. For that reason, it is preferable that the sulphur content of the steel is below 0.015%, preferably below 0.010%, even more preferably below 0.005.
  • the phosphor content is below 0.03%, more preferably below 0.02%.
  • the invention is also embodied in a cartridge case for a rimfire cartridge, the cartridge case having a cylindrical wall and a closed base, a circumferential bulge at the base extending radially outwardly from the cylindrical wall and having an opening into the interior of the cartridge case, wherein the cartridge case comprises substantially of steel and wherein the cartridge case cylindrical wall is at least 10 % thinner than a comparable brass cartridge case sidewall.
  • the steels considered were low carbon steel, medium carbon steel and high strength steel having a yield strength of 242, 300 and 400 MPa respectively, whereas brass has a yield strength of 142 MPa. It was found that the lower strength steels performed better than the higher strength steels, but all steels resulted in a thinner gauge of the steel shell cylinder wall in comparison to the much thicker brass shell cylinder wall and showed similar performance to the brass shell in terms of extraction properties.
  • Low carbon steel cartridges were produced by cold rolling and recrystallisation annealing between 500 and 980 0 C followed by temper rolling to a final gauge of 0.0118" (0.3 mm). Temper rolling reductions are chosen up to 12%. Preferably the minimum temper rolling reduction is 1%. A preferable maximum for temper rolling is 7%, more preferably 5%. By temper rolling the steel strip, the yield strength of the steel increases, thereby reducing the yield strength/tensile strength ratio.
  • the steel strips were provided on one or both sides with a thin nickel-zinc alloy (NiZn) coating or a Brass coating, a coating layer having a coating thickness preferably ranging between 0 and 200 ⁇ " (5.08 ⁇ m).
  • the coating thickness is between 50 (1.27 ⁇ m) and 150 ⁇ " (3.81 ⁇ m), more preferably between 80 (2.03 ⁇ m) and 120 ⁇ " (3.05 ⁇ m).
  • Samples produced from a 1006 low carbon steel thus produced were successfully converted into rimfire cartridges and provided excellent firing and extraction properties.

Landscapes

  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Filling Or Discharging Of Gas Storage Vessels (AREA)

Abstract

La présente invention concerne une cartouche à percussion annulaire comprenant un étui de cartouche essentiellement en acier.
PCT/EP2007/004584 2006-05-23 2007-05-23 Douilles de munition a percussion annulaire WO2007134855A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US80252606P 2006-05-23 2006-05-23
US60/802,526 2006-05-23

Publications (1)

Publication Number Publication Date
WO2007134855A1 true WO2007134855A1 (fr) 2007-11-29

Family

ID=38355533

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/EP2007/004584 WO2007134855A1 (fr) 2006-05-23 2007-05-23 Douilles de munition a percussion annulaire

Country Status (1)

Country Link
WO (1) WO2007134855A1 (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2016100440A3 (fr) * 2014-12-16 2016-09-01 Greer Steel Company Compositions d'acier, procédés de fabrication et utilisations de production de cartouches à percussion annulaire

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB438311A (en) * 1934-05-23 1935-11-14 Armes De Guerre Fab Nat Improvements in sporting cartridges
US2522208A (en) * 1946-06-26 1950-09-12 Remington Arms Co Inc Ammunition
US3659528A (en) * 1969-12-24 1972-05-02 Texas Instruments Inc Composite metal cartridge case

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB438311A (en) * 1934-05-23 1935-11-14 Armes De Guerre Fab Nat Improvements in sporting cartridges
US2522208A (en) * 1946-06-26 1950-09-12 Remington Arms Co Inc Ammunition
US3659528A (en) * 1969-12-24 1972-05-02 Texas Instruments Inc Composite metal cartridge case

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2016100440A3 (fr) * 2014-12-16 2016-09-01 Greer Steel Company Compositions d'acier, procédés de fabrication et utilisations de production de cartouches à percussion annulaire
US10676801B2 (en) 2014-12-16 2020-06-09 Greer Steel Company Steel compositions, methods of manufacture and uses in producing rimfire cartridges
EP3754033A1 (fr) * 2014-12-16 2020-12-23 Greer Steel Company Cartouches à percussion annulaire et procédé de fabrication de cartouche à percussion annulaire
US11905569B2 (en) 2014-12-16 2024-02-20 Greer Steel Company Steel compositions, methods of manufacture and uses in producing rimfire cartridges

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