US3730094A - Energetic protective coating for caseless ammunition - Google Patents
Energetic protective coating for caseless ammunition Download PDFInfo
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- US3730094A US3730094A US00045743A US3730094DA US3730094A US 3730094 A US3730094 A US 3730094A US 00045743 A US00045743 A US 00045743A US 3730094D A US3730094D A US 3730094DA US 3730094 A US3730094 A US 3730094A
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- Prior art keywords
- coating
- energetic
- caseless
- ammunition
- propellant
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- 239000011253 protective coating Substances 0.000 title description 9
- 239000002360 explosive Substances 0.000 claims abstract description 15
- 238000000576 coating method Methods 0.000 abstract description 38
- 239000011248 coating agent Substances 0.000 abstract description 25
- 239000003380 propellant Substances 0.000 abstract description 21
- 230000007613 environmental effect Effects 0.000 abstract description 10
- 230000008901 benefit Effects 0.000 abstract description 6
- 230000004308 accommodation Effects 0.000 abstract description 4
- 239000000203 mixture Substances 0.000 description 20
- 239000000463 material Substances 0.000 description 10
- XTFIVUDBNACUBN-UHFFFAOYSA-N 1,3,5-trinitro-1,3,5-triazinane Chemical compound [O-][N+](=O)N1CN([N+]([O-])=O)CN([N+]([O-])=O)C1 XTFIVUDBNACUBN-UHFFFAOYSA-N 0.000 description 6
- 239000008199 coating composition Substances 0.000 description 5
- 230000000694 effects Effects 0.000 description 5
- 238000001704 evaporation Methods 0.000 description 5
- 239000008187 granular material Substances 0.000 description 5
- 239000007788 liquid Substances 0.000 description 5
- 238000000034 method Methods 0.000 description 5
- 239000000020 Nitrocellulose Substances 0.000 description 4
- 229910052751 metal Inorganic materials 0.000 description 4
- 239000002184 metal Substances 0.000 description 4
- 229920001220 nitrocellulos Polymers 0.000 description 4
- 239000000725 suspension Substances 0.000 description 4
- ZWEHNKRNPOVVGH-UHFFFAOYSA-N 2-Butanone Chemical compound CCC(C)=O ZWEHNKRNPOVVGH-UHFFFAOYSA-N 0.000 description 3
- CSCPPACGZOOCGX-UHFFFAOYSA-N Acetone Chemical compound CC(C)=O CSCPPACGZOOCGX-UHFFFAOYSA-N 0.000 description 2
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 2
- FERIUCNNQQJTOY-UHFFFAOYSA-N Butyric acid Chemical compound CCCC(O)=O FERIUCNNQQJTOY-UHFFFAOYSA-N 0.000 description 2
- RTZKZFJDLAIYFH-UHFFFAOYSA-N Diethyl ether Chemical compound CCOCC RTZKZFJDLAIYFH-UHFFFAOYSA-N 0.000 description 2
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 2
- 239000002253 acid Substances 0.000 description 2
- 239000011230 binding agent Substances 0.000 description 2
- 229920002301 cellulose acetate Polymers 0.000 description 2
- 230000008030 elimination Effects 0.000 description 2
- 238000003379 elimination reaction Methods 0.000 description 2
- 238000004880 explosion Methods 0.000 description 2
- 238000010304 firing Methods 0.000 description 2
- 238000007654 immersion Methods 0.000 description 2
- 230000006872 improvement Effects 0.000 description 2
- 150000002739 metals Chemical class 0.000 description 2
- 230000008569 process Effects 0.000 description 2
- SMZOUWXMTYCWNB-UHFFFAOYSA-N 2-(2-methoxy-5-methylphenyl)ethanamine Chemical compound COC1=CC=C(C)C=C1CCN SMZOUWXMTYCWNB-UHFFFAOYSA-N 0.000 description 1
- NIXOWILDQLNWCW-UHFFFAOYSA-N 2-Propenoic acid Natural products OC(=O)C=C NIXOWILDQLNWCW-UHFFFAOYSA-N 0.000 description 1
- NLHHRLWOUZZQLW-UHFFFAOYSA-N Acrylonitrile Chemical compound C=CC#N NLHHRLWOUZZQLW-UHFFFAOYSA-N 0.000 description 1
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
- CERQOIWHTDAKMF-UHFFFAOYSA-N Methacrylic acid Chemical compound CC(=C)C(O)=O CERQOIWHTDAKMF-UHFFFAOYSA-N 0.000 description 1
- VVQNEPGJFQJSBK-UHFFFAOYSA-N Methyl methacrylate Chemical compound COC(=O)C(C)=C VVQNEPGJFQJSBK-UHFFFAOYSA-N 0.000 description 1
- 241001291960 Myroides Species 0.000 description 1
- 206010035148 Plague Diseases 0.000 description 1
- 241000607479 Yersinia pestis Species 0.000 description 1
- 150000007513 acids Chemical class 0.000 description 1
- 239000000853 adhesive Substances 0.000 description 1
- 230000001070 adhesive effect Effects 0.000 description 1
- 239000010425 asbestos Substances 0.000 description 1
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 1
- 239000004568 cement Substances 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 229920001577 copolymer Polymers 0.000 description 1
- 125000004122 cyclic group Chemical group 0.000 description 1
- 230000002939 deleterious effect Effects 0.000 description 1
- 238000007598 dipping method Methods 0.000 description 1
- 150000002148 esters Chemical class 0.000 description 1
- 239000004744 fabric Substances 0.000 description 1
- 239000010439 graphite Substances 0.000 description 1
- 229910002804 graphite Inorganic materials 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- WETZJIOEDGMBMA-UHFFFAOYSA-L lead styphnate Chemical compound [Pb+2].[O-]C1=C([N+]([O-])=O)C=C([N+]([O-])=O)C([O-])=C1[N+]([O-])=O WETZJIOEDGMBMA-UHFFFAOYSA-L 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 230000007246 mechanism Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- CWQXQMHSOZUFJS-UHFFFAOYSA-N molybdenum disulfide Chemical compound S=[Mo]=S CWQXQMHSOZUFJS-UHFFFAOYSA-N 0.000 description 1
- 229910052982 molybdenum disulfide Inorganic materials 0.000 description 1
- 150000002823 nitrates Chemical class 0.000 description 1
- 229910052757 nitrogen Inorganic materials 0.000 description 1
- 150000002894 organic compounds Chemical class 0.000 description 1
- 239000001301 oxygen Substances 0.000 description 1
- 229910052760 oxygen Inorganic materials 0.000 description 1
- 239000012188 paraffin wax Substances 0.000 description 1
- 239000008188 pellet Substances 0.000 description 1
- 238000009527 percussion Methods 0.000 description 1
- 230000001141 propulsive effect Effects 0.000 description 1
- 230000000979 retarding effect Effects 0.000 description 1
- 229910052895 riebeckite Inorganic materials 0.000 description 1
- 239000002904 solvent Substances 0.000 description 1
- 238000005507 spraying Methods 0.000 description 1
- 230000006641 stabilisation Effects 0.000 description 1
- 238000011105 stabilization Methods 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
- 229920001169 thermoplastic Polymers 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
- 238000004078 waterproofing Methods 0.000 description 1
Images
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
- F42B5/02—Cartridges, i.e. cases with charge and missile
- F42B5/18—Caseless ammunition; Cartridges having combustible cases
- F42B5/192—Cartridge cases characterised by the material of the casing wall
- F42B5/196—Coatings
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10S102/00—Ammunition and explosives
- Y10S102/70—Combustilbe cartridge
Definitions
- This invention relates to a protective coating for caseless ammunition and particularly, to a thermaland moisture-resistant coating for caseless ammunition which provides good environmental protection. More particularly, the invention relates to caseless ammunition components provided with'energetic environmental protective coatings.
- a caseless cartridge consist essentially of a cartridge body or rigid charge formed of any suitable explosive substance and that such body or charge be completely consumable and constitute either the whole or a part of the propulsive charge.
- caseless cartridges providing means for the appropriate attachment of projectiles and primer caps and possessing mass burning rate and ballistic characteristics comparable to those possessed by metal cased rounds of similar caliber and propellant.
- the present invention is concerned with an energetic coating composition for providing caseless ammunition components with environmental protection, said composition consisting essentially of a high temperature resistant explosive.
- the invention also contemplates a liquid coating mixture for application to caseless ammunition components to provide environmental protective coatings therefor, said mixture consisting essentially of a suspension in an organic medium of an energetic composition consisting essentially of a high temperature resistant explosive.
- the invention is further directed to a process for providing caseless ammunition components with environmental protection comprising applying a liquid coating mixture to said components to provide a wet coating thereon, said mixture consisting essentially of a suspension in an organic medium of an energetic composition consisting essentially of a high temperature resistant explosive, evaporating said organic medium, from said wet coating to obtain a dry coating, and repeating said mixture applying and organic medium evaporating steps until a desired coating thickness is obtained.
- the invention is also directed to a process for providing a caseless round with environmental protection comprising applying a liquid coating mixture to the individual components thereof to provide wet coatings thereon, said mixture consisting essentially of a suspension in an organic medium of an energetic composition consisting essentially of a high temperature resistant explosive, evaporating said organic medium from said wet coatings to obtain dry coatings, repeating said mixture applying and evaporating steps until a desired coating thickness is obtained, assembling said individual components to form said caseless round, and repeating'said mixture applying and evaporating steps with respect to the assembled round.
- the invention also relates to a caseless round characterized by improved environmental protection comprising an assembly of components wherein each of said components as well as the assembled round are provided with an energetic coating composition consisting essentially of a high temperature resistant explosive.
- the underlying concept of the present invention resides in the proposition that the substitution of an energetic coating for the non-energetic, caseless ammunition protective coating of the prior art offers the advantage that no consumability accommodation is required in the ballistic cycle.
- An added advantage stems from the thermal resistance afforded by the thicker coatings without undesirable effects on the ballistic cycle.
- FIGURE depicts a sectional view in elevation of a small caliber caseless round coated in accordance with the invention.
- a molded propellant It has the usual projectile 11 adhesively secured in a recess thereof.
- the adhesive may be of any wellknown combustible type, such as Duco cement, for example, which is a nitrocellulose dissolved in methyl ethyl ketone, and having no deleterious effects upon the molded propellant.
- the projecle may partake of any suitable small arms type, that shown being a typical jacketed type for receiving the impressions of the lands and grooves to effect stabilization
- An axial cavity 12 if formed within the round and is generally centrally disposed therewithin as shown.
- a primer 13 is received within an axial recess 14 of substantially the same diameter as cavity 12 but is separated therefrom by a wall 15 comprising the original integrally molded propellant.
- the wall 15 supports primer 13 when it receives an impact from a firing pin, not shown.
- a coating 17, in accordance with the present invention, is applied to the propellant components and 13 by spraying, dipping, etc.
- a final coat is also applied to the assembled round.
- the primer 13 is suitable of the type disclosed in U. S. Pat. No. 3,l87,67l (Scanlon et-al.) issued June 8, 1965, and containing a lead styphnate type mix ignited by a percussion cap enclosed between thin sheets of paper.
- the configurations of some of the original propellant granules are shown at 16.
- the propellant composition employed in the molded propellant components discussed herein forms no part of the present invention and may be any of the myroid of compositions typically used for caseless ammunition. Examples thereof are found in Propellant Chemistry" by Stanly F. Sarner, Reinhold Publ. Co., New York (1966), pages 108 ll 1.
- a suitable technique for binding propellant granules together to form molded caseless ammunition components is disclosed by Quinlan et al., infra, using a binder, such as collodion comprising 5% nitrocellulose of 7-l0% nitrogen content, the balance being 50-50 mixture of ethanol and ethyl ether.
- a binder such as collodion comprising 5% nitrocellulose of 7-l0% nitrogen content, the balance being 50-50 mixture of ethanol and ethyl ether.
- Such a binder is less energetic than the propellant granules and possesses a slower burning rate.
- the coating composition of the present invention consists essentially of an explosive which is resistant to high temperatures and is desirably selected from the group consisting of nitro-organics and nitrate esters. These organic compounds incorporate oxygen into the molecule in an energetic form and consequently, the coatings prepared therewith are regarded as energetic coatings, thatis, coatings which during the course of the ballistic cycle have the net effect of supplying energy to the propulsion system.
- the nitro-organics and particularly, the cyclic nitro-organics such as RDX and HMX are preferred explosives for the inventive coating compositions.
- RDX has the formula [CH NNO and is named trinitrotrimethylenet riamine commonly called cyclonite
- HMX has the formula [cl-l NNO- h and is named tetranitrotetramethylenetetramine, commonly called homocyclonited.
- Other suitable high temperature resistant explosives include those described by Sarner, infra, pages 278 299.
- the explosive material forming the essential component thereof is mixed with an inert material, that is, a non-energetic material which is 'consumable during the ballistic cycle and does not detrimentally affect same.
- Suitable materials in this regard comprise thermoplastic polymers and copolymers of acrylic acid, butyric acid, methacrylic acid, esters of these acids, and acrylonitrile.
- a preferred non-energetic material is cellulose acetate.
- the proportion of non-energetic material employed in the coating is such that the minimum employed is sufficient to provide the desired thermal resistance while the maximum employed does not detract from the net effect of supplying energy to the propulsion system.
- the coating may consist of parts by weight of explosive acid and up to about 20 parts weight of non-energetic material.
- EXAMPLE I A mixture of 20 parts by weight of cellulose acetate and 80 parts by weight of RDX is prepared and added to acetone to form a suspension. The liquid mixture is then employed to provide a protective coating for a 7.62mm caseless round comprising a projectile, a ho]- low cylindrical, molded propellant body and a combustible primer assembly, consisting of primer cup, primer pellet and propellant disc seal.
- the molded propellant components employ nitrocellulose granules bound by collodion as described by Quinlan et al., infra, and are coated by immersion in the liquid mixture, the propellant body component being provided with a suitable plug to prevent coating of the interior wall surfaces.
- the solvent is evaporated from the wet coatings by heating at l22F for 30 minutes.
- the coating procedure is repeated until a coating thickness of about 5 mils is obtained.
- the coated components together with the projectile are then assembled to form a round and a final coating is applied as aforementioned.
- the resultant round exhibits adequate moisture resistance as evidenced by ability tobe fired after immersion in water.
- the applied coating is high temperature resistant as evidenced by an explosion temperature at least 50C.. higher than the explosion temperature of the molded propellant.
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- Engineering & Computer Science (AREA)
- General Engineering & Computer Science (AREA)
- Paints Or Removers (AREA)
Abstract
Caseless ammunition comprising propellant components provided with an energetic thermal and moisture-resistant coating are characterized by good environmental protection. The employment of a high temperature resistant explosive as a component of the coating permits the application of relatively thick coatings to obtain the advantage of increased thermal resistance without a consumability accommodation in the ballistic cycle.
Description
11mm States afienfi 1191 g [1 1 3,73,@@% Qninian 51 May 1, 1973 i [54] ENERGETIC PROTECTIVE COATING 3,504,630 4/1970 Picard ..149/93 x FOR CASELESS AMMUNITION r Prima Examiner-RobertF Stahl 751 t: 0sehB.ul Phldlh,P. 1 or J Q m 1 a e p a Attorney-Harry M. Saragovitz, Edward J. Kelly, Her- [73] Ass1gnee: The United States of America as be Berland D b ff represented by the Secretary of the Army 7 57 ABSTRACT [22] Flled: June 1970 Caseless ammunition comprising propellant com- [21] Appl. No.: 45,743 ponents provided with an energetic thermal and moisture-resistant coating are characterized by good 52 us. (:1. ..102/38, 102/43 P, lO2/DlG. 1 envimnmemal Protection The employment Of a high 51 1m. (:1 ..F42b 5/18 temperature resistant explosive as a component of the 58 Field of Search ..l02/38, DIG. 1,43, Coating permits the application of relatively thick 102/39; 149/2 coatings to obtain the advantage of increased thermal resistance without a consumability accommodation in [5 6] References Cited the ballistic cycle.
UNITED STATES PATENTS 3 Claims, 1 Drawing Figure 2,966,405 12/1960 Sloan 149/92 3,397,637 8/l968 Bobinski et al. ..lO2/DIG. l
Patented May 1, 1973 3,730,094
INVENTOR, JOSEPH B. QUINLAN ATTORNEYS:
ENERGETIC PROTECTIVE COATING FOR CA'SELESS AMMUNITION The invention described herein may be manufactured, used, and licensed by or for the Government for governmental purposes without the payment to me of 5 any royalty thereon.
BACKGROUND OF THE INVENTION 1. FIELD OF THE INVENTION This invention relates to a protective coating for caseless ammunition and particularly, to a thermaland moisture-resistant coating for caseless ammunition which provides good environmental protection. More particularly, the invention relates to caseless ammunition components provided with'energetic environmental protective coatings.
2. DESCRIPTION OF THE PRIOR ART Caseless ammunition, i.e., ammunition having a consumable or combustible cartridge case is well known and the advantages thereof vis-a-vis cased rounds are discussed at length in the prior art, e.g., U. S. Pat. No. 2,982,211. (Beal et al.), issued May 2, 1961 and U. S. Pat. No. 3,212,440 (Quinlan et al.) issued Oct. 19, 1965. In general these advantages comprise a considerable saving in ammunition weight, obviation of the case disposal problem, increased weapon firing rate potential and weapon weight attributable to elimination of the ejection operation and mechanism, and elimination of the need for expensive cartridge case metals and metal forming operations as well as the need for stockpiling such metals to avoid critical shortages.
The concept of a caseless cartridge is not of recent vintage, as evidenced by the disclosure of British Pat. No. 7193 AD. 1891. The British specification sets forth the generally accepted criteria that a caseless cartridge consist essentially of a cartridge body or rigid charge formed of any suitable explosive substance and that such body or charge be completely consumable and constitute either the whole or a part of the propulsive charge.
Since the original concept, improvements in the design and fabrication of caseless ammunition have been the subject of numerous patents. For example, Beal et al., infra, disclose caseless cartridges providing means for the appropriate attachment of projectiles and primer caps and possessing mass burning rate and ballistic characteristics comparable to those possessed by metal cased rounds of similar caliber and propellant.
' While progress in the development and improvement of caseless ammunition is borne out by the aforementioned discussion, a particularly vexing problem has attended the use of such ammunition from the outset and has continued to plague investigators in their attempts to provide a solution therefor. This problem relates to environmental protection for caseless ammunition and is basically concerned with imparting thermal and moisture resistance to caseless cartridges. While. recognitionof the problem is not original, prior art attempts have not been wholly satisfactory. In the main, they have provided only partial environmental protection while concomitantly compromising the ballistic performance characteristics of the caseless cartridges. In this regard, the British specification, infra, discloses coating the exterior surface of a caseless cartridge with e an incombustible material, such as paraffin or asbestos cloth, to improve thermal resistance and, accordingly,
necessarily effects thereby an accommodation in the ballistic cycle. Beal et al, infra, suggest the application of a protective coating to a laminated combustible cartridge case for the purpose of waterproofing or, in some instances, as a means of controlling or retarding the burning rate of the combustible case, although lacking in a teaching of a specific coating composition that will accomplish the desired results. Quinlan et al, infra, teach the application of a thin coating, not more than 0.002 inch thick, of a suitable material to the outer surfaces of propellant to reduce heat conductivity from the weapon chamber to the round and thus reduce the danger of cook-off. Suggested coating materials by Quinlan et al. include percent by weight of methyl methacrylate and the balance molybdenum disulfide or graphite. As the Quinlan et al. coatings are necessarily restricted to relatively thin dimensions in order to insure adequate combustibility and ballistic performance, the degree of thermal resistance afforded by such coatings is minimal, and consequently, constitutes an unduly limiting design factor.
SUMMARY OF THE INVENTION The present invention is concerned with an energetic coating composition for providing caseless ammunition components with environmental protection, said composition consisting essentially of a high temperature resistant explosive.
The invention also contemplates a liquid coating mixture for application to caseless ammunition components to provide environmental protective coatings therefor, said mixture consisting essentially of a suspension in an organic medium of an energetic composition consisting essentially of a high temperature resistant explosive.
The invention is further directed to a process for providing caseless ammunition components with environmental protection comprising applying a liquid coating mixture to said components to provide a wet coating thereon, said mixture consisting essentially of a suspension in an organic medium of an energetic composition consisting essentially of a high temperature resistant explosive, evaporating said organic medium, from said wet coating to obtain a dry coating, and repeating said mixture applying and organic medium evaporating steps until a desired coating thickness is obtained.
The invention is also directed to a process for providing a caseless round with environmental protection comprising applying a liquid coating mixture to the individual components thereof to provide wet coatings thereon, said mixture consisting essentially of a suspension in an organic medium of an energetic composition consisting essentially of a high temperature resistant explosive, evaporating said organic medium from said wet coatings to obtain dry coatings, repeating said mixture applying and evaporating steps until a desired coating thickness is obtained, assembling said individual components to form said caseless round, and repeating'said mixture applying and evaporating steps with respect to the assembled round.
The invention also relates to a caseless round characterized by improved environmental protection comprising an assembly of components wherein each of said components as well as the assembled round are provided with an energetic coating composition consisting essentially of a high temperature resistant explosive.
The underlying concept of the present invention resides in the proposition that the substitution of an energetic coating for the non-energetic, caseless ammunition protective coating of the prior art offers the advantage that no consumability accommodation is required in the ballistic cycle. An added advantage stems from the thermal resistance afforded by the thicker coatings without undesirable effects on the ballistic cycle.
DESCRIPTION OF THE DRAWING The FIGURE depicts a sectional view in elevation of a small caliber caseless round coated in accordance with the invention.
DETAILED DESCRIPTION Referring now to the single FIGURE of the drawing wherein a sectional view in elevation of a preferred embodiment of the invention is shown, a molded propellant It) has the usual projectile 11 adhesively secured in a recess thereof. The adhesive may be of any wellknown combustible type, such as Duco cement, for example, which is a nitrocellulose dissolved in methyl ethyl ketone, and having no deleterious effects upon the molded propellant. The projecle may partake of any suitable small arms type, that shown being a typical jacketed type for receiving the impressions of the lands and grooves to effect stabilization An axial cavity 12 if formed within the round and is generally centrally disposed therewithin as shown.
A primer 13 is received within an axial recess 14 of substantially the same diameter as cavity 12 but is separated therefrom by a wall 15 comprising the original integrally molded propellant. The wall 15 supports primer 13 when it receives an impact from a firing pin, not shown. A coating 17, in accordance with the present invention, is applied to the propellant components and 13 by spraying, dipping, etc. A final coat is also applied to the assembled round.
The primer 13 is suitable of the type disclosed in U. S. Pat. No. 3,l87,67l (Scanlon et-al.) issued June 8, 1965, and containing a lead styphnate type mix ignited by a percussion cap enclosed between thin sheets of paper. The configurations of some of the original propellant granules are shown at 16.
The propellant composition employed in the molded propellant components discussed herein forms no part of the present invention and may be any of the myroid of compositions typically used for caseless ammunition. Examples thereof are found in Propellant Chemistry" by Stanly F. Sarner, Reinhold Publ. Co., New York (1966), pages 108 ll 1.
A suitable technique for binding propellant granules together to form molded caseless ammunition components is disclosed by Quinlan et al., infra, using a binder, such as collodion comprising 5% nitrocellulose of 7-l0% nitrogen content, the balance being 50-50 mixture of ethanol and ethyl ether. Such a binder is less energetic than the propellant granules and possesses a slower burning rate.
The coating composition of the present invention consists essentially of an explosive which is resistant to high temperatures and is desirably selected from the group consisting of nitro-organics and nitrate esters. These organic compounds incorporate oxygen into the molecule in an energetic form and consequently, the coatings prepared therewith are regarded as energetic coatings, thatis, coatings which during the course of the ballistic cycle have the net effect of supplying energy to the propulsion system. The nitro-organics and particularly, the cyclic nitro-organics such as RDX and HMX are preferred explosives for the inventive coating compositions. RDX has the formula [CH NNO and is named trinitrotrimethylenet riamine commonly called cyclonite, while HMX has the formula [cl-l NNO- h and is named tetranitrotetramethylenetetramine, commonly called homocyclonited. Other suitable high temperature resistant explosives include those described by Sarner, infra, pages 278 299.
For the purpose of improving the high temperature resistance of the inventive coatings, the explosive material forming the essential component thereof is mixed with an inert material, that is, a non-energetic material which is 'consumable during the ballistic cycle and does not detrimentally affect same. Suitable materials in this regard comprise thermoplastic polymers and copolymers of acrylic acid, butyric acid, methacrylic acid, esters of these acids, and acrylonitrile. A preferred non-energetic material is cellulose acetate. The proportion of non-energetic material employed in the coating is such that the minimum employed is sufficient to provide the desired thermal resistance while the maximum employed does not detract from the net effect of supplying energy to the propulsion system. In general, the coating may consist of parts by weight of explosive acid and up to about 20 parts weight of non-energetic material.
EXAMPLE I A mixture of 20 parts by weight of cellulose acetate and 80 parts by weight of RDX is prepared and added to acetone to form a suspension. The liquid mixture is then employed to provide a protective coating for a 7.62mm caseless round comprising a projectile, a ho]- low cylindrical, molded propellant body and a combustible primer assembly, consisting of primer cup, primer pellet and propellant disc seal. The molded propellant components employ nitrocellulose granules bound by collodion as described by Quinlan et al., infra, and are coated by immersion in the liquid mixture, the propellant body component being provided with a suitable plug to prevent coating of the interior wall surfaces. Thereafter, the solvent is evaporated from the wet coatings by heating at l22F for 30 minutes. The coating procedure is repeated until a coating thickness of about 5 mils is obtained. The coated components together with the projectile are then assembled to form a round and a final coating is applied as aforementioned. The resultant round exhibits adequate moisture resistance as evidenced by ability tobe fired after immersion in water. Further, the applied coating is high temperature resistant as evidenced by an explosion temperature at least 50C.. higher than the explosion temperature of the molded propellant.
EXAMPLE n The procedure of Example I is carried out with the exception that I-IMX is substituted for RDX. Comparable results are obtained.
I wish it to be understood that I do not desire to be limited to-the exact details of construction shown and described, for obvious modifications will occur to a person skilled in the art.
I claim: a
1. In a caseless round of ammunition having a molded propellant charge of nitrocellulose granules and a projectile adhesively secured within a forward portion thereof, said molded propellant charge having a rearwardly opening recess in a rearward end thereof,
Claims (2)
- 2. The structure of claim 1 wherein said explosive is RDX.
- 3. The structure of claim 1 wherein said explosive is HMX.
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
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US4574370A | 1970-06-12 | 1970-06-12 |
Publications (1)
Publication Number | Publication Date |
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US3730094A true US3730094A (en) | 1973-05-01 |
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US00045743A Expired - Lifetime US3730094A (en) | 1970-06-12 | 1970-06-12 | Energetic protective coating for caseless ammunition |
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Cited By (18)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3847081A (en) * | 1972-12-20 | 1974-11-12 | Us Army | Ammunition |
US3877374A (en) * | 1973-07-12 | 1975-04-15 | Olin Corp | Protective coating for caseless ammunition |
US3927616A (en) * | 1974-04-23 | 1975-12-23 | Us Army | Combustible cartridge case |
DE2458877A1 (en) * | 1974-12-12 | 1976-06-24 | Deutsch Franz Forsch Inst | COMBUSTIBLE PROTECTIVE COVER AGAINST THERMAL INFLUENCES FOR DRIVING CHARGES WITHOUT METAL CARTRIDGE |
US3987731A (en) * | 1976-01-16 | 1976-10-26 | The United States Of America As Represented By The Secretary Of The Army | Composite protective coating for combustible cartridge cases |
US4010690A (en) * | 1973-04-30 | 1977-03-08 | Avco Corporation | Means for and method of providing a fire protection for a caseless ammunition |
FR2383421A1 (en) * | 1977-03-10 | 1978-10-06 | Rheinmetall Gmbh | SURFACE PROTECTION FOR COMBUSTIBLE SOCKET AMMUNITION OR SOCKETLESS AMMUNITION |
JPS55124000A (en) * | 1979-03-17 | 1980-09-24 | Kazuhide Sakurada | Cartridge |
US4263070A (en) * | 1973-01-17 | 1981-04-21 | Thiokol Corporation | Thermally stable gun and caseless cartridge propellants |
US4365558A (en) * | 1978-12-15 | 1982-12-28 | Societe Nationale Des Poudres Et Explosifs | Combustible objects, in particular combustible cartridge cases, which are heat-resistant |
WO1986002347A1 (en) * | 1984-10-10 | 1986-04-24 | Kurtz Earl F | Explosive composition and method |
US4728376A (en) * | 1982-11-01 | 1988-03-01 | Golden Power Of Texas, Inc. | Explosive composition and method |
US4964929A (en) * | 1986-11-27 | 1990-10-23 | Hoffmann-La Roche Inc. | Preparation of explosives containing degradation products of ascorbic or isoascorbic acid |
US4997496A (en) * | 1989-06-13 | 1991-03-05 | Hoffmann-La Roche Inc. | Explosive and propellant composition and method |
US5237927A (en) * | 1991-10-21 | 1993-08-24 | Olin Corporation | Energetic consumable cartridge case |
US5608982A (en) * | 1994-12-12 | 1997-03-11 | Giat Industries | Method and apparatus for an electric arc firing system for caseless ammunition |
US5970877A (en) * | 1998-03-02 | 1999-10-26 | Hensler; Jerry | Gun propellant coating |
US6524706B1 (en) * | 2001-03-27 | 2003-02-25 | The United States Of America As Represented By The Secretary Of The Army | Reduction of energetic filler sensitivity in propellants through coating |
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US2966405A (en) * | 1955-01-03 | 1960-12-27 | Atlantic Res Corp | Cellulose ester propellant compositions |
US3397637A (en) * | 1967-02-08 | 1968-08-20 | Army Usa | Combustible and consumable cartridge cases |
US3504630A (en) * | 1968-03-14 | 1970-04-07 | Us Army | Combustible cartridge with fibrous porous base having crystalline explosive disposed therein |
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1970
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Publication number | Priority date | Publication date | Assignee | Title |
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US2966405A (en) * | 1955-01-03 | 1960-12-27 | Atlantic Res Corp | Cellulose ester propellant compositions |
US3397637A (en) * | 1967-02-08 | 1968-08-20 | Army Usa | Combustible and consumable cartridge cases |
US3504630A (en) * | 1968-03-14 | 1970-04-07 | Us Army | Combustible cartridge with fibrous porous base having crystalline explosive disposed therein |
Cited By (21)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3847081A (en) * | 1972-12-20 | 1974-11-12 | Us Army | Ammunition |
US4263070A (en) * | 1973-01-17 | 1981-04-21 | Thiokol Corporation | Thermally stable gun and caseless cartridge propellants |
US4010690A (en) * | 1973-04-30 | 1977-03-08 | Avco Corporation | Means for and method of providing a fire protection for a caseless ammunition |
US3877374A (en) * | 1973-07-12 | 1975-04-15 | Olin Corp | Protective coating for caseless ammunition |
US3927616A (en) * | 1974-04-23 | 1975-12-23 | Us Army | Combustible cartridge case |
DE2458877A1 (en) * | 1974-12-12 | 1976-06-24 | Deutsch Franz Forsch Inst | COMBUSTIBLE PROTECTIVE COVER AGAINST THERMAL INFLUENCES FOR DRIVING CHARGES WITHOUT METAL CARTRIDGE |
FR2294421A1 (en) * | 1974-12-12 | 1976-07-09 | Saint Louis Inst | Thermal effects resisting combustible envelope for propellant charge - consists of plastics foam with secondary explosives |
US3987731A (en) * | 1976-01-16 | 1976-10-26 | The United States Of America As Represented By The Secretary Of The Army | Composite protective coating for combustible cartridge cases |
US4363273A (en) * | 1977-03-10 | 1982-12-14 | Rheinmetall Gmbh | Ammunition with protective surface layer and method of making same |
FR2383421A1 (en) * | 1977-03-10 | 1978-10-06 | Rheinmetall Gmbh | SURFACE PROTECTION FOR COMBUSTIBLE SOCKET AMMUNITION OR SOCKETLESS AMMUNITION |
US4452653A (en) * | 1977-03-10 | 1984-06-05 | Rheinmetall Gmbh | Method of coating ammunition with a protective surface layer |
US4365558A (en) * | 1978-12-15 | 1982-12-28 | Societe Nationale Des Poudres Et Explosifs | Combustible objects, in particular combustible cartridge cases, which are heat-resistant |
JPS55124000A (en) * | 1979-03-17 | 1980-09-24 | Kazuhide Sakurada | Cartridge |
US4728376A (en) * | 1982-11-01 | 1988-03-01 | Golden Power Of Texas, Inc. | Explosive composition and method |
WO1986002347A1 (en) * | 1984-10-10 | 1986-04-24 | Kurtz Earl F | Explosive composition and method |
US4964929A (en) * | 1986-11-27 | 1990-10-23 | Hoffmann-La Roche Inc. | Preparation of explosives containing degradation products of ascorbic or isoascorbic acid |
US4997496A (en) * | 1989-06-13 | 1991-03-05 | Hoffmann-La Roche Inc. | Explosive and propellant composition and method |
US5237927A (en) * | 1991-10-21 | 1993-08-24 | Olin Corporation | Energetic consumable cartridge case |
US5608982A (en) * | 1994-12-12 | 1997-03-11 | Giat Industries | Method and apparatus for an electric arc firing system for caseless ammunition |
US5970877A (en) * | 1998-03-02 | 1999-10-26 | Hensler; Jerry | Gun propellant coating |
US6524706B1 (en) * | 2001-03-27 | 2003-02-25 | The United States Of America As Represented By The Secretary Of The Army | Reduction of energetic filler sensitivity in propellants through coating |
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