Key information

Title
PROJECTILE FOR A RIFLED BARREL WEAPON
Application number
20160816
Case type
National
Status
31.05.2019 P.g.a ikke betalt årsavgift
Filed
13.05.2016
Effective date
13.05.2016
Publicly available
14.11.2017
Applicant
JH Engineering AS (NO)
Inventor
Johans Hamarsnes (NO) et al.
Agent
ONSAGERS AS (NO)

Abstract and drawing

Disclaimer: This text has been machine-scanned and may contain errors – please refer to "Publications" for legally binding content.
The present invention relates to a projectile suited for rifled barrel weapons made from a homogenous, coherent and non-porous matrix material håving a composition comprising Fe > 99.400 weight% and C < 0.035 weight%, based on the total weight of the matrix material.

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Date
 Date Doc. No. Process Case number In/Out Journal description To/from
 17.12.2019 13-01 Saksbehandling 20160816 UT PT Endelig henlagt for ikke betalt årsavgift (3313)
01.10.2019 12-01 Saksbehandling 20160816 UT PT Påminnelse om ikke betalt årsavgift (3329) (PT20160816)
03.04.2018 11-01 Saksbehandling 20160816 UT PT Batch Varsel om betaling av første årsavgift (3317)
26.06.2017 08-01 Saksbehandling 20160816 UT Bekreftelse på patentsøknad Onsagers AS
 22.06.2017 10-02 Saksbehandling 20160816 INN Hovedbrev Onsagers AS
 22.06.2017 10-01 Saksbehandling 20160816 INN Korrespondanse (Hovedbrev inn) Onsagers AS
 22.06.2017 09-01 Saksbehandling 20160816 INN Korrespondanse (Hovedbrev inn) Onsagers AS
 03.06.2017 07-01 Saksbehandling 20160816 UT Realitet patent Onsagers AS
 26.05.2017 06-04 Saksbehandling 20160816 INN Beskrivelse med sporing Onsagers AS
 26.05.2017 06-03 Saksbehandling 20160816 INN Hovedbrev Onsagers AS
 26.05.2017 06-02 Saksbehandling 20160816 INN Beskrivelse Onsagers AS
 26.05.2017 06-01 Saksbehandling 20160816 INN Korrespondanse (Hovedbrev inn) Onsagers AS
 26.11.2016 05-02 Saksbehandling 20160816 UT PT report 10:04:18
26.11.2016 05-01 Saksbehandling 20160816 UT Realitet patent Onsagers AS
 27.06.2016 04-01 Saksbehandling 20160816 UT Infobrev til oppfinner Onsagers AS
 23.06.2016 03-04 Saksbehandling 20160816 INN Fullmakt Onsagers AS
 23.06.2016 03-03 Saksbehandling 20160816 INN Erklæring Søkers rett til oppfinnelse Onsagers AS
 23.06.2016 03-02 Saksbehandling 20160816 INN Hovedbrev Onsagers AS
 23.06.2016 03-01 Saksbehandling 20160816 INN Korrespondanse (Hovedbrev inn) Onsagers AS
 20.05.2016 02-01 Saksbehandling 20160816 UT Formalia 1 Onsagers AS
 13.05.2016 01-03 Saksbehandling 20160816 INN Beskrivelse
13.05.2016 01-02 Saksbehandling 20160816 INN Tegninger
13.05.2016 01-01 Saksbehandling 20160816 INN Søknadsskjema Patent

Description, claims and drawings

Disclaimer: This text has been machine-scanned and may contain errors – please refer to "Publications" for legally binding content. Description
The present invention relates to a projectile suited for rifled barrel weapons.A projectile may obtain significantly more accurate trajectory and increased firing range by setting the projectile in rapid rotation around its longitudinal centre axis, and thus create a gyro-stabilising effect on the projectile. Weapons firing projectiles are therefore usually equipped with a rifled barrel, i.e. one or several helical grooves running along the inner surface of the barrel.The raised sections of the helical grooves are often denoted as "lands". The lands are the part of the barrel that engraves into the surface of the projectile, and thus responsible for setting the projectile in rotation when it advances through the barrel. Such rifled barrel weapons are typically rifles, guns, revolvers etc. However, also artillery weapons have such rifled barrels.Ammunition for rifled barrel weapons usually comprises a cartridge, an igniter (primer), a propellant and a projectile. Some projectiles are made of a single material; such projectiles can be referred to as massive material projectiles or non-jacket projectiles. Other projectiles, for example the full metal jacket projectiles, have a soft core typically made of lead and a hard shell or jacket extending around the core. The jacket is the only part in contact with the barrel and is subject to the engraving of the lands, and is made of metals or alloys such as copper or copper alloys.Projectiles will better utilise the energy of the propellant if it forms a substantially gas tight closure between the projectile and the barrel, i.e. preventing propellant gases to bypass the projectile when advancing through the barrel. Projectiles for rifled barrel weapons should thus be correspondingly dimensioned and be made of materials that are able to deform to enable a close and tight fitting to the inner dimensions of the barrel, both at and in-between the lands. That is, the projectile should have mechanical properties ensuring that its surface region deforms to give space for the lands without inducing excessive wear on the barrel/lands. Another consideration is that projectiles should be made of materials with sufficient mechanical integrity to avoid disintegrating upon exposure to the heavy strains during firing of the weapon.Another consideration is the friction forces between the projectile surface and the inner surface of the barrel. If the friction is too high the barrel will suffer more wear and there is a risk that the projectile will require a too high force to overcome the frictional resistance between the barrel and the projectile resulting in low and inconsistent muzzle velocities and correspondingly high gas pressures in the propellant gases. In the worst case scenarios the gas pressure may exceed the strength of the barrel material resulting in severe damage of the barrel. There is thus a ceiling on the maximum friction force between the projectile and the barrel during firing of the weapon which is accepted.Further, the projectiles need to avoid leaving residues of jacket material in the barrel after firing. This is caused by the partial melting of the jacket material generated by the friction between the barrel and the projectile. The melting temperature of the jacket should thus not be too low. Moreover, they should have sufficiently high density to ensure acceptable impact energies and provide a sufficiently strong gyro-stabilising of the projectile's trajectory towards its target.There are thus a set of constraints on the mechanical properties of materials to be used for projectiles in rifle barrelled weapons. Up to date, these demands have usually been met by employing lead or alloyed lead as the bulk material of projectiles, both for jacketed and non-jacketed projectiles. The jacket is usually made of a copper alloy. Both copper and lead are however toxic, both to the user and the environment. From a hunter's perspective copper and lead may also, to some extent, contaminate the meat of the prey. Thus, there is a need and desire for finding non-toxic materials suited for use in projectiles.As known to a person skilled in the art of gunnery, the typical construction of small arms ammunition for rifled barrel weapons, such as a rifle, a gun, a revolver, artillery weapons etc, is as shown schematically in Figure 1 a) and Figure 1 b). The ammunition 1 typically comprises a casing 2, an igniter 3, propellant 4 and a projectile 5. The propellant 4 is normally provided as a powder inside the casing 2. From Figure 2, it is shown that prior art projectiles 5 intended for military use typically comprises a core 6, usually made of lead, and a jacket 7, usually made of copper.There is an increased desire and political pressure in the society for reducing the pollution from toxic metals in the nature. The present standard ammunition for small arms, both for military and civil purposes, contains lead in the projectile either alone, or in combination with a copper jacket. Both lead and copper are toxic, such that shooting ranges and military training facilities may save significant costs by changing to non-toxic materials in the projectiles and thus avoid the need for håving ground water protection measures such as collection of drainage water run-off, etc.The challenge with lead-free projectiles is to find materials with similar properties as lead, i.e. high weight, low hardness and friction. Tungsten (Wolfram) or tungsten-based materials (for example tungsten carbide, ferrotungsten etc.) are materials being used in order to replace lead in projectiles.From document US 2 805 624 it is known a method comprising pressing and sintering a fraction of spherical iron particles håving a relatively large diameter of 300 - 400 microns and a fraction håving smaller diameter of about 80 microns together with a suitable binder to form a substantially non-porous briquette adapted for use as projectiles for ammunition cartridges. The density of the projectiles is disclosed to be approaching the density of pure iron, i.e. a density of 7.75 g/cm3 as compared to 7.86 g/cm3 of pure iron. The projectiles are reported to be less eroding on the gun barrel than prior art projectiles made from iron powders, which are believed to be due to the heterogeneous surface of the projectile resulting from the relatively soft iron particles bound together with smaller iron particles.Document DE 20 2005 017039 teaches a projectile for air guns made by thermoforming/hot working a wire of pure iron. The projectiles may be coated with another metal, for example copper, tin or a polymer as corrosion protection.The main objective of the present invention is to provide a non-toxic non-jacketed projectile suited for rifle barrelled firing weapons.Moreover, it is an objective of the invention to provide a lead and copper-free non-jacketed projectile acceptable for military use within the Geneva Convention of 1949, and which has more or less similar properties as the ordinary copper jacketed projectiles used today.A further objective of the invention is to provide a projectile with improved trajectory precision and target penetration ability as compared to ordinary copper jacketed projectiles used today.The invention is based on the discovery made by the inventor that certain iron qualities containing high fractions of the a-ferrite phase mimic the mechanical properties of copper reasonably well, such that non-jacketed projectiles made from a single homogeneous and coherent lump of a matrix material håving a high fraction of a-ferrite constitutes an excellent substitute for the common ammunition comprising lead based projectiles with a copper jacket presently employed by the armed forces and in most civil applications. Tests performed by the inventor have shown that such matric material has excellent mechanical properties for forming projectiles which may attain superior performance in terms of trajectory precision and target penetration ability as compared to present standard military ammunition for rifle barrelled weapons consisting of a lead core and a copper mantle.Thus in a first aspect, the present invention relates to a projectile for weapons with rifled barrels, comprising:- one section (13) shaped into a right circular cylinder of substantially radius, r, and length, L, along a longitudinal axis of the elongated body, and- the body (11) consists of a homogenous, coherent and non-porous matrix material håving a composition comprising Fe > 99.400 weight% and C < 0.035 weight%, based on the total weight of the matrix material.Ammunition will be handled, stored and operated at typical outdoor temperatures up to a maximum of around 70 °C. At these temperatures, the iron -carbon system only exists in the solid phase. As can bee seen from the phase diagram at these temperatures, the thermodynamically stable phases of a matrix material håving a composition comprising Fe > 99.400 weight% and C < 0.035 weight%, are either consisting of a pure a-ferrite phase when the carbon content is below the solid solubility of carbon, or a mixture of the a-ferrite phase and minor amounts of the pearlite phase when the carbon content is above the solid solubility of carbon.A-ferrite is a single phase, solid solution of carbon atoms at interstitial sites in a body-centred cubic crystal lattice of iron-atoms. Due to the relatively huge size of C-atoms as compared to interstitial sites in the Fe-lattice, the body-centred cubic crystal lattice of iron-atoms has limited capacity for taking up carbon-atoms, such that the solubility of C is only 0.005 weight% C at 0 °C and increases with temperature up to a maximum at 727 °C of 0.022 weight% C [2]. The a-ferrite phase, or alpha-iron as it also is denoted in the literature, is a ferromagnetic, soft and ductile form of iron. The a-ferrite phase exists up to a temperature of 910 °C. In the phase diagram shown in Figure 2 [1], the a-ferrite phase is located far to the left and is due to the low carbon content difficult to distinguish from the ordinate axis of the phase diagram.Pearlite is a two-phased interpenetrating microstructure of about 88 weight% a-ferrite and 12 weight% cementite. Cementite is another name for iron carbide, FesC, which is very a hard and brittle material. The mechanical properties of pearlite phase are thus an intermediate between the hard and brittle cementite, and the soft and ductile a-ferrite.Experiments performed by the inventor have indicated that some amount of the pearlite phase may be accepted in the projectile without significantly compromising the mechanical properties of the projectile. More precisely, the tests have indicated that matrix materials håving a Vickers hardness of 150 HVio or less (tested according to the standard; ISO 6507-1:2005 using a load of 10 kg), are well suited for forming homogenous, coherent and non-porous projectiles. Such projectiles are sufficiently soft to be used in rifled barrel weapons without inducing inacceptable wear or inacceptable high friction against on the lands of the barrel. The limit of Vickers hardness of 150 HVio or less is a preferred (i.e. not a mandatory) feature of the present invention. Projectiles håving somewhat higher hardness may be applied, but they will not function equally well due to higher friction forces against the barrel. In practice, the preferred hardness of the matrix material is obtained by a matrix material håving a composition comprising one of the following ranges: Fe > 99.400 weight% and C < 0.035 weight%;Fe > 99.400 weight% and C < 0.030 weight%;Fe > 99.400 weight% and C < 0.025 weight%;Fe > 99.400 weight% and C < 0.020 weight%;Fe > 99.400 weight% and C < 0.015 weight%;Fe > 99.400 weight% and C < 0.008 weight%;Fe > 99.400 weight% and C < 0.005 weight%;Fe > 99.400 weight% and C < 0.0005 weight%;Fe > 99.400 weight% and C from 0.0005 to 0.020 weight%;The matrix material of either of the above given ranges of iron and carbon contents, may advantageously be alloyed by one or more of the following elements within the given alloying ranges; Si < 0.15 weight%, Mn < 0.20 weight%, S < 0.04 weight%, P < 0.05 weight%, Cu < 0.03 weight%, Sr < 0.01 weight%, Al < 0.02 weight%, Ti < 0.02 weight%, and Nb < 0.05 weight%. Impurities and other elements may advantageously be kept below a total amount of 0.489 weight%. All weight%-units refer to the total mass of the iron phase.The alloying elements may have an effect of the hardness of the matrix material, such that, depending on which and the amount of alloying element being applied, the alloying elements may induce a restriction of the maximum carbon content of the matrix material to avoid a hardness of the matrix material above the preferred range. The determination of which alloying elements to be applied at which amounts in an iron alloy to obtain a preferred hardness, is within the ordinary skills of a person skilled in the art. Likewise, the handling and heat treatment of iron alloys may have a profound effect on their hardness. The person skilled in the art is well aware of this effect and how to avoid hardening an iron material, i.e. how to obtain an iron material comprising substantially the a-ferrite phase.The term "homogenous, coherent and non-porous matrix material" as used herein, means that the matrix material is a single lump or piece of a continuous and massive material håving no measurable porosity. Furthermore, the term "the matrix material is substantially composed of the a-ferrite phase" as used herein, means that the matrix material has a composition ranging from only single phased a-ferrite to a composite phase of mostly a-ferrite phase and some pearlite phase within the above given ranges for the carbon content, optionally also including one or more of the above given alloying elements within the above given alloying ranges; Si, Mn, S, P, Cu, Sr, Al, Ti, and Nb. Preferably, the matrix material may advantageously have a hardness in one of the following ranges; from 60 to 150 HVio, from 60 to 140 HVio, from 70 to 130 HVio, from 80 to 120 HVio, from 90 to 115 HVio.The term "right circular cylinder section (13) of substantially radius r and length L" as used herein, means that a part of the projectile is shaped into a regular right circular cylinder within practical limits for industrial production. That is, the term "right circular cylinder" is not to be interpreted in the strict mathematical sense of the term. Slight deviations in the radius (and thus diameter) within one or two orders of magnitude of microns may occur along the length L of section (13). Section (13) is the part of the projectile which will be in contact with the inner wall of the barrel and be mildly deformed by the lands of the rifled barrel. Thus the radius r and the length L of section (13) must be adapted to the dimensions of the barrel and chamber of the actual weapon. However, the present invention is not bounded by any limit of r and L. The projectile according to the invention may be made into any known and conceivable calibre for present and future rifle barrelled weapons, ranging from small firearms to heavy artillery. Examples of suited calibres includes, but is not limited to, calibre 22, 5.56x45mm NATO, 7.62x51mm NATO, 9mm NATO, .223 Remington, and 12.7x99mm NATO.Also, even though the projectile of the invention is suited as substitute for present projectiles for rifle barrelled weapons, it may of course be applied for non-rifle barrelled weapons. The dimensioning of the projectile, including the adaption of the radius r and the length L, is within the ordinary skills of a person skilled in the art.The projectile according to the present invention obtains its favourable mechanical properties by the choice of material, i.e. the single homogenous, coherent and non-porous iron phase of the projectile. Thus the projectile of the invention may be employed as is, i.e. without any surface coating, due to the favourable softness and ductility combined with the excellent mechanical integrity of the a-ferrite phase enabling firing the projectile in a weapons with a rifled barrel without inducing unacceptable damage/wear on the lands and/or the inner surface of the barrel, or without leaving any residues of the projectile inside the barrel.However, a-ferrite phase iron has a poor corrosion resistance. Surface corrosion, and in particular rust, is highly detrimental to the friction performance of the projectile and induces unacceptable wear on the barrel, and needs to be avoided. The projectile of the invention may thus advantageously be coated with a corrosion protective coating to ease the storing and handling of the projectile, i.e. to ease the precautions required to avoid the surface of the projectile from corroding during storing and handling. The corrosion protective coating may be any known or conceivable coating able to protect iron from being corroded upon contact with e.g. moisture/water and oxygen. The corrosion protective coating may have any thickness as long as the diameter of the coated projectile is within the dimension specifications of ammunition. In practice, the coating may advantageously have a thickness of less than 100 um, preferably less than 50 um, more preferably less than 25 um, most preferably less than 15 um. The corrosion protective layer may be deposited or formed in any known or conceivable manner known to a person skilled in the art. Examples of suited methods includes, but is not limited to; chemical vapour deposition, plasma enhanced vapour deposition, sputtering, etc.The corrosion protective coating may provide a further beneficial effect by being a an intermediate "barrier layer" between the iron phase of the projectile and the steel phase of the barrel which reduces the friction forces between the inner surface of the barrel and the surface of the projectile. A lowered friction is advantageous by reducing the wear on the barrel and by giving the projectile an increased and more consistent muzzle velocity and thus improved target penetration ability and trajectory accuracy. Thus it is preferred to include a corrosion protective layer håving a friction reducing effect on the projectile according to the invention, but this should not be considered as a mandatory and essential feature of the present invention since the corrosion protection of the projectiles may be obtained by other means (by e.g. ensuring the projectile is stored and handled without contact with moisture/water) and the projectile may be fired without any layer on its surface.Examples of suited corrosion protective coatings which has the beneficial of reduced friction includes, but is not limited to, one of the following materials: vapour deposited a-C:Cr + a-C:H, vapour deposited diamond like carbon, tin, molybdenum disulphide, and polytetrafluoroethylene (PTFE). PTFE is often sold under the trademark name TEFLON®.An especially preferred corrosion protective coating is a coating sold under the trademark name XYLAN®1424/F9426 BLACK, supplied by Whitford Plastics Ltd of 10, Christleton Court, Manor Park, WA7 IST Manor Park, Cheshire, England. XYLAN®1424/F9426 BLACK is an aqueous based, resin-bonded dry-film lubricant coating containing polytetrafluoroethylene and may be applied by spraying or bulk deposition (including electrodeposition) techniques. Substrate preparation is limited to a solvent wash or vapour degreasing. The especially preferred coating of XYLAN®1424/F9426 BLACK may be deposited onto the projectile of the invention by spraying in a chamber at 180 °C until a layer of dried XYLAN®1424/- F9426 BLACK of thickness in the range from 1 to 25 um, preferably from 5 to 20 um, more preferably from 10 to 15 um, and most preferred from 12 to 13 um covers the surface of the projectile. The thicknesses are given for the coating in the dry and cured state after drying at 180 °C - 200 °C for a period of 200 minutes or more. If the curing/drying temperature is increased to 220 °C, the curing times may be considerably shorter. The XYLAN®1424/F9426 BLACK is not recommended cured and dried at higher temperatures.The projectile according to the invention is to be regarded as a non-jacketed projectile since the coating on the projectile body is too thin to give any significant contribution to the mechanical properties of the projectile with the exception of the friction towards the barrel. Thus, it is the projectile body which provides the required softness and mechanical integrity allowing the projectile to function as ammunition for barrelled weapons. This means that the projectile body should have a softness and ductility allowing it to deform by the lands of the barrel to form a gas tight closure with the barrel and at the same time a mechanical resilience allowing the projectile to withstand the acceleration forces during firing of the weapon and then to withstand the drag forces during the flight towards the target without decomposing or deforming (more than caused by the lands).Any known or conceivable process for shaping the single homogenous, coherent and non-porous matrix material of the invention into projectiles may be utilised by the present invention, both hot processes involving melting and solidification and cold processes. This includes, but is not limited to; moulding or box casting molten iron or iron alloys into work pieces for projectile bodies, casting molten iron or iron alloys into ingots that are subsequently processed into several work pieces for projectile bodies. The work pieces may be machined in any known or conceivable way to obtain the intended dimension and geometry of the projectile, for example by being machined directly from ingot bars to correct projectile geometry in a lathe, etc.An example embodiment of the projectile according to the invention, håving a corrosion protective coating, is illustrated schematically in Figure 3. The projectile 10 is made of one continuous iron phase 11 and is given a design which comprises a section 13 being a right circular cylinder of radius r and length L along the longitudinal centre axis indicated by the stapled line from A to A'. The front section (14) of the projectile is tapered to form a nose of the projectile. The corrosion protective coating is indicated by the thick line marked with reference number 12.It should be noted that the dimension of the projectile will be dependent on the characteristics of the weapon. The specific type of ammunitions or the specific types of weapons will not be described herein as this is considered known to a person skilled in the art.Fig. 1 a) and b) illustrate a cross section of a prior art type of ammunition; Fig. 2 is a phase diagram of the Fe-C system;Fig. 4 is a photo of an example embodiment of the projectile after firing; Fig. 5 corresponds to fig. 4, where the lands markings on the projectile are indicated; Fig. 6 is a diagram showing curves indicating the press force needed to press standard NM255 steel-cored projectiles through a section of a gun barrel; Fig. 7 is a diagram showing curves indicating the press force needed to press projectiles according to an example embodiment of the invention through the same section of a gun barrel as the tests shown in Figure 6; Fig. 8a) is a photograph of a paper target applied in a test firing of samples of projectiles of the invention. Fig. 8b) is a photograph of a paper target applied in a comparison test firing of samples of standard NM255 projectiles.The invention will be described in further detail by way of example embodiments of the invention.The first example embodiment of the invention is schematically illustrated in Figures 4 and 5, which are photographs of the projectile after firing. Reference number 10 is the general reference to the projectile, 11 is the body and 12 is the coating. Reference number 20a, 20b and 20c are the land marks, i.e. areas where a portion of the body 12 is worn off and/or deformed due to contact with the lands of the barrel. The photograph of Figure 5 shows the same example as in Figure 4, but contains white lines to better indicate the land marks 20a, 20b and 20c.The body 11 was of direct reduced iron with less than 0.015 % carbon made by reducing fine grained hematite or magnetite iron ore with hydrogen as reducing gas, rolled to cylindrical bars of diameter 6 mm. The bars were cut into 30 mm long ingots or work pieces, where each was machined into a projectile body of 5.56 mm diameter and total length of 24.75 mm. Then a 1 to 5 um thick layer of diamond like carbon of type <x-C:Cr + <x-C:H was deposited by plasma enhanced vapour deposition. As shown by the black colour on the photographs, the coating was mainly applied at the right circular cylinder section of the projectile.A set of projectiles håving dimensions and shape corresponding to projectiles of standard NM255 ammunition (5.56x45 mm) were machined in a lathe, from round bars of diameter 0 10 mm. The bars were made from a single homogenous, coherent and non-porous iron phase of substantially ferrite, with a Vickers hardness of 115 HVio, håving a composition of: C = 0.0132 weight%, Si = 0.0887 weight%, Mn = 0.155 weight%, P = 0.00052 weight%, S = 0.0039 weight%, Cr = 0.013 weight%, Ni = 0.021 weight%, Cu 0.0118 weight%, Nb = 0.0025 weight%, Ti = 0.0607n weight%. Fe = 99.63 weight%. Other minor impurities together were ca. 0.006 weight%. The projectiles were spray ed with XYLAN®1424/F9426 BLACK and dried and cured at 180 °C for 150 minutes. The resulting coating had a thickness of 12 um.Then friction between the projectiles and a gun barrel was measured by pressing samples of the projectiles at a constant velocity of 0.5 mm/s through a 50 mm long section of a machine gun barrel by a piston, and registering the force needed to press the projectile through the barrel. A total of five tests were made on the second example embodiment of the invention and five equal tests were made on projectiles of standard NM255 ammunition, which have a steal core and copper jacket.The obtained test results are given in chronological order in Table 1. "BM-1" stands for the first sample of the second example embodiment of the invention while "NM255-1" stands for the first sample of the standard projectile. The obtained pressure curves as a function of displacement through the gun barrel are shown in Figure 6 for the standard NM255 projectiles and in Figure 7 for the projectiles of the second example embodiment. As seen from the Table 1 and Figures 6 and 7, the projectile of the second example embodiment has a friction against the barrel of nearly one fifth of the standard NM255 projectiles.Four samples of the same set of projectiles were test fired by mounting a HK 416 assault rifle in a rig and shooting at a paper target at a distance of 100 m. Figure 8 a) is a photograph of the paper target showing the trajectory accuracy of the four test specimens of the invention. The result corresponds to an accuracy of 0.9 minutes of angle (MOA). A minute of angle corresponds to a trajectory deviation of 26.59 mm at 100 m firing range.As a comparison, four samples of standard NM 255 ammunition were fired in the same rig. Figure 8 b) is a photograph of the paper target applied in the comparison test. This result corresponds to an accuracy of 2.1 MOA.The test also involved four test firings with the same test rig and weapon of the same caliber ammunition with present standard military ammunition håving a lead core and copper mantle. For these test firings, we do not have a photograph of the paper target, but the test firings gave an accuracy of 1.9 MOA.3. http: / / pur eir onmetal. weebly. com/index. html
Claims
1. A projectile for rifle barrelled weapons, comprising: - an elongated body (11) håving cylindrical symmetry and which comprises: - one section (13) shaped into a right circular cylinder of substantially radius, r, and length, L, along a longitudinal axis of the elongated body, and - one section (14) shaped into a projectile nose,characterised in that - the elongated body (11) consists of a homogenous, coherent and non-porous matrix material håving a composition comprising Fe > 99.400 weight% and C < 0.035 weight%, based on the total weight of the matrix material.2. Projectile according to claim 1, wherein the composition of the homogenous, coherent and non-porous matrix material is within one of the following ranges, based on the total weight of the iron phase: Fe > 99.400 weight% and C < 0.030 weight%; Fe > 99.400 weight% and C < 0.025 weight%; Fe > 99.400 weight% and C < 0.020 weight%; Fe > 99.400 weight% and C < 0.015 weight%; Fe > 99.400 weight% and C < 0.008 weight%; Fe > 99.400 weight% and C < 0.005 weight%; Fe > 99.400 weight% and C < 0.0005 weight%; Fe > 99.400 weight% and C from 0.0005 to 0.020 weight%; Fe > 99.400 weight% and C from 0.008 to 0.035 weight%, Fe > 99.400 weight% and C from 0.008 to 0.030 weight%, Fe > 99.400 weight% and C from 0.008 to 0.025 weight% or Fe > 99.400 weight% and C from 0.008 to 0.020 weight%.3. Projectile according to claim 1 or 2, wherein the composition of the homogenous, coherent and non-porous matrix material further comprises one or more of the following elements within the given ranges, based on the total weight of the iron phase; Si < 0.15 weight%, Mn < 0.20 weight%, S < 0.04 weight%, P < 0.05 weight%, Cu < 0.03 weight%, Sr < 0.01 weight%, Al < 0.02 weight%, Ti < 0.02 weight%, and Nb < 0.05 weight%.4. Projectile according to claim 3, wherein the total content of impurities and other elements other than Fe and C is kept below a total amount of 0.489 weight%, based on the total weight of the iron phase.5. Projectile according to any preceding claim, wherein the homogenous, coherent and non-porous matrix material is substantially composed of the a-ferrite phase.6. Projectile according to any preceding claim, wherein the matrix material has Vickers hardness, as measured by ISO 6507-1:2005 using a load of 10 kg, of 150 HVio or less.7. Projectile according to claim 6, wherein the matrix material has Vickers hardness in one of the following ranges; from 60 to 150 HVio, from 70 to 140 HVio, from 80 to 130 HVio, from 80 to 120 HVio, from 90 to 115 HVio.8. Projectile according to any preceding claim, wherein the elongated body (11) is coated by corrosion protective coating (12).9. Projectile according to claim 8, wherein the thickness of the corrosion protective coating is in one of the following ranges; of less than 100 um, preferably less than 50 um, more preferably less than 25 um, most preferably less than 15 um.10. Projectile according to claim 8 or 9, wherein the corrosion protective coating is made of one of the following materials: vapour deposited a-C:Cr + a-C:H, vapour deposited diamond like carbon, tin, molybdenum disulphide, or polytetrafluoroethylene (PTFE).11. Projectile according to claim 8 or 9, wherein the corrosion protective coating is made of a coating obtained by spraying the projectiles with a coating sold under the trademark name XYLAN®1424/F9426 BLACK followed by drying and curing the deposited coating.12. Projectile according to claim 11, wherein the deposited XYLAN®1424/F9426 BLACK coating is håving a thickness, after drying and curing, in the range from 1 to 25 um, preferably in the range from 5 to 20 um, more preferably in the range from 10 to 15 um, and most in the range preferred from 12 to 13 jim.13. Projectile according to claim 12, wherein the dimensions of the elongated body is dimensioned and shaped corresponding to 5.56x45 mm ammunition and the composition of the matrix material comprises: 0.0132 weight% C, 0.0887 weight% Si, 0.155 weight% Mn, 0.00052 weight% P, 0.0039 weight% S, 0.013 weight% Cr,0.021 weight% Ni, 0.0118 weight% Cu, 0.0025 weight% Cu, 0.0607 weight% Ti, and 99.62 weight% Fe, the rest being impurities.
Drawings

Priority

No priority

Patent classes

IPC classesF42B 12/74CPC classesF42B 12/74

Citations

US 4109581 A (A)- ()US 5686693 A (A)WO 8604135 A (A)WO 9400730 A (A)

Applicants, owners and inventors

Applicants
JH Engineering AS
Grimsrudveien 22 2830 RAUFOSS NO (VESTRE TOTEN Municipality, Innlandet county)Org. number: 995665409Inventors
Johans Hamarsnes
Grimsrudvegen 22 2830 RAUFOSS NO (VESTRE TOTEN Municipality, Innlandet county)
Sveinung Gihle Raddum
Skjølaasvegen 192 2860 HOV NO (SØNDRE LAND Municipality, Innlandet county)

Agent

ONSAGERS AS
ONSAGERS AS

Org. number: 934603729

Name and address are automatically synchronized with the Brønnøysund Register Centre.

Open in The Brønnøysund Register Centre
Postboks 1813, Vika 0123 OSLO NO (OSLO Municipality, Oslo county)
Org. number: 934603729
Reference: P23153NO01

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