Brass Cartridge Cases Research Articles

Cleaning deteriorated elements of ammunition: Development of a procedure applied to cartridge cases from the Second World War

Deteriorated elements of ammunition can be found while investigating different types of events. Exposure to adverse environmental conditions may lead to metal alteration (corrosion) or organic material deposition (contaminations) on the exposed elements of ammunition. From a forensic perspective, both types of deterioration pose challenges when observing marks left by the firearms used to discharge the corresponding ammunition (e.g. firing pin, extractor). The longer the time of exposure to the adverse environmental conditions, the more challenging the observation of such marks. A literature review highlighted three previously published restorative methods used to clean deteriorated elements of ammunition. The aim of this research is to develop a cleaning procedure applicable to cartridge cases exposed to adverse environmental conditions, while avoiding the degradation of marks left by the firearms used to discharge the corresponding ammunition. A first batch of 21 brass cartridge cases dating back to the Second World War (WWII) was used to develop a cleaning sequence involving the three methods. The efficiency of each restorative method was qualitatively assessed using optical macroscopy and the Evofinder® ballistic identification system. The developed sequence relies on successive applications of Tickopur® TR 7 (a diluted soft metal cleaner), sulfuric acid and finally Aqua Regia (HCl 37% and HNO3 75%), all of them involving ultrasonic baths. The resulting cleaning sequence was subsequently applied to three batches of Second World War cartridge cases discovered in France and Russia. This sequential procedure allows the effective cleaning of WWII brass cartridge cases while highlighting different marks left by firing pins, extractors, ejectors, and breech faces. Applying a forensic analysis and comparison process to the marks highlighted on these elements of ammunition can support the verification of historical facts when reconstructing events which took place more than seventy years ago.

A low‐potential electrochemical method for fast development of latent fingerprints on brass cartridge cases by electrodeposition of poly(3,4‐ethylenedioxythiophene)

AbstractThe electrodeposition of poly(3,4‐ethylenedioxythiophene) (PEDOT) for development of latent fingerprints on brass cartridge cases may be successfully performed, even though the simultaneous corrosion process of copper and zinc from the brass surface occurs. PEDOT is electrodeposited by direct oxidation of the monomer in aqueous LiClO4 solution using chronoamperometry (potentiostatic method) with experimental conditions set at 0.90 V versus Ag/AgCl and 180 seconds. Such strategy is interesting for application in forensic biometrics for development of latent fingerprints on brass cartridge cases, since it affords images with high definition, allowing a clear visualization of the ridge patterns and singular points, besides to be useful for confrontation in fingerprint databases. Therefore, this is a simple, efficient, fast, low‐potential, and low‐cost methodology for the processing of cartridge cases.

Light Weight Aluminum Cartridge Case Design for IED’s Application - ANSYS

This paper describes the design analysis of the aluminum cartridge case, its testing, Analytical Simulation (ANSYS) and evaluation against Improvised Explosive Devices (IEDs) applications. Aluminum material is light in weight, non-corrosive and compatible with the propellant. Because of excellent properties, it is widely used in defence application sector. In the armament system, an effort is being made to reduce the cost, the weight of material from logistic point of view and its manufacturing process so as to meet the design requirements. Brass cartridge cases are being widely used in various types of ammunition for last 100 years e.g. armaments of small arm cartridges, artillery shell and power cartridges for fighter aircraft. Cartridges are made of either aluminum, steel or brass is filled with the propellants and pyrotechnic composition. With suitable means of ignition, the propellant generates the hot combustion gases at high pressure and temperature. These combustion gases are utilized to perform certain work on the system. The aluminum cartridge case for water disruptor applications plays a significant role in the destruction of the suspicious objects. This paper discusses the design aspects of the aluminum cartridge case for disruptor application of suspected IEDs. Performance evaluation parameters i.e. maximum pressure (Pmax) and time to reach maximum pressure (TPmax) of aluminum cartridge have been carried out in a Closed Vessel (CV) using a Data Acquisition System (DAS). The material properties of aluminum such as tensile strength, percentage elongation and yield strength are determined using a Universal Testing Machine (UTM). Using the data obtained by the above methods, an attempt has been made to determine stress, strain and deformation of the cartridge case theoretically and numerically using ANSYS software. The results obtained by both methods are compared. The results are in good agreement with each other. It is observed that the percentage error for von -Mises stresses is 10.2 % using numerical and theoretical approaches. The percentage error between numerical and theoretical values of the hoop and longitudinal stresses are 6.71 % and 6.78 %. The percentage error between numerical and theoretical values of the hoop and longitudinal strains are 1.36 % and 3.64 %. The errors between theoretical and numerical values for radial displacements are 2.83 %. The novelty in this research work is that the design analysis of aluminium cartridge case is carried out using ANSYS software simulating the real- world problem. The analytical results are compared with numerical results. The actual pressure experienced by the cartridge case generated by the propellant burning is taken into consideration. This pressure is measured by a pressure transducer fitted over a specially designed test rig using a DAS. The sample of aluminum case is tested for hardness and microstructure. The results show there is no significant difference before and after the hardness and microstructure of the material. The results of ANSYS for stress and strain are in good agreement with theoretically calculated results and numerical analysis as percentage error is less than 11. This draws the inference for validating numerical and theoretical results. It is seen that 57.352 % saving in weight using aluminum cartridge is achieved. Using ANSYS, hoop stress 382.7 MPa, Hoop strain 4.32x10-3, longitudinal strain 0.8602x10-3 and longitudinal stress 191.5 MPa are estimated. The main objective of this paper is to carry out design and analysis of aluminum cartridge case analytically as well as numerically.

The effects of soaking for DNA recovery on the striation patterns of fired cartridge cases

ABSTRACTThe recovery of trace DNA from fired cartridge cases has recently gained increased interest throughout the literature, with a variety of methods currently being explored. Soaking fired cartridge cases in a lysis buffer holds potential in producing meaningful DNA profiles; however, chemical interactions between the lysis buffer and brass cartridge cases may limit the efficacy of this method. This preliminary study examines the effects of soaking on the microscopic striation detail of brass and nickel 9 mm Parabellum (9 mmP) calibre and .22 Long Rifle (.22LR) calibre fired cartridge cases. Headstamp and coarse striation patterns on 9 mmP fired cartridge cases and finer striation patterns along the outer wall of .22LR fired cartridge cases were microscopically examined prior to and following soaking. Soaking was performed by submerging the fired cartridge cases in 380 µl of ATL buffer (Qiagen, Germany) for 20 minutes. Microscopic analysis of brass and nickel 9 mmP and .22LR fired cartridge cases showed that coarse and fine striation detail remain unaffected following soaking. These results indicate that comparative ballistics examinations may be performed following DNA recovery using the soaking method.

Analysis of Structural State of 60/40 Brass Cartridge Case (BCC) after Being Exposed to High Pressure and Temperature of Firing

This research presents an experimental and analytical study of the structural state of the 60/40 brass cartridge case, (BCC) after being fired. The oral section of the BCC has the function of confining the gases of firing by expanding against the chamber and sealing the gases. Firing conditions, namely, high pressure and temperature, 3000 bar and 2727°C, respectively, affect performance properties of the (BCC). These are confining and crack strengths. Experimental study was done on the oral section to address these effects on the structural and mechanical properties of this brass. This alloy is a 60% copper (Cu) and 40% zinc (Zn) alloy and has a two-phase structure, alpha, (α) and beta, (β). Using “before and after” comparison approach; performance properties were tested in cartridge cases prepared before and after firing. These properties are hardness, tensile strength, micro-structural and chemical composition. Comparing the tests’ results, after firing demonstrated considerable degrading in performance properties, micro-structural disorder and a remarkable deficiency in the zinc element in the brass structure. This deficiency affects the percentage of beta phase in the alloy which governs the strength of the brass. According to the required properties before firing, it was found that after firing, the brass cartridge case is not qualified for reloading.

Recovery of latent fingermarks from brass cartridge cases: Evaluation of developers, analysis of surfaces and internal ballistic effects

A study was undertaken wherein different fingermark developers were evaluated for the recovery of fingermarks from brass cartridge cases, besides the evaluation of factors such as firing effects and surface characterization of the cases. The latent fingermarks on α-brass plates, fired and unfired cartridge cases were deposited and aged for 1–14days before development with different developers. In order to mimic the fired cartridge case conditions, the brass plates were heated and examined at room temperature (RT), at 63 and at 200°C. The sequential treatment with cyanoacrylate, gun blue and fluorescent dye has been found to be the best among other developers for the recovery of latent fingermarks on brass surfaces including fired and unfired cartridge cases. Cartridge cases and other brass surfaces were also analyzed by surface characterization methods, including X-ray diffraction, scanning electronic microscopy, energy dispersive X-ray spectroscopy and metallographic examination. The tested surfaces correspond to α-phase brass Cu0.7Zn0.3 composition and have shown different surface morphologies (such as grain structure) and different levels of oxidation, even for cartridge cases obtained from the same batch. Due to this, the effectiveness of a given reagent for a specific brass surface is uncertain. Therefore, the application of the entire tested sequence of developers is strongly recommended. Further, the effects of firing on fingermarks on cartridge cases were examined, and the results indicated that the blowback of hot gases through the looseness between cartridge case and chamber wall of the firearm is the main cause responsible for deterioration of fingermarks during firing. Despite the recognized damage caused to fingermarks by the firing effects, good quality fingermarks were recovered from fired cartridge cases in which full fingermarks were intentionally deposited prior to firing. This indicates that the handling of the cartridges before and during the loading of the gun may have a strong influence on the quantity and quality of fingermarks, and that the firing itself is not the main responsible factor for the absence or low quality of fingermarks, as frequently reported in fired cartridge cases studies.

A novel method for the photographic recovery of fingermark impressions from ammunition cases using digital imaging.

The photographic preservation of fingermark impression evidence found on ammunition cases remains problematic due to the cylindrical shape of the deposition substrate preventing complete capture of the impression in a single image. A novel method was developed for the photographic recovery of fingermarks from curved surfaces using digital imaging. The process involves the digital construction of a complete impression image made from several different images captured from multiple camera perspectives. Fingermark impressions deposited onto 9-mm and 0.22-caliber brass cartridge cases and a plastic 12-gauge shotgun shell were tested using various image parameters, including digital stitching method, number of images per 360° rotation of shell, image cropping, and overlap. The results suggest that this method may be successfully used to recover fingermark impression evidence from the surfaces of ammunition cases or other similar cylindrical surfaces.

Deterring gun crime materially using forensic coatings

Surface coatings that can help deter and solve gun crime are described. These nanoengineered coatings have been applied and evaluated on brass cartridge cases, where they increase associative forensic evidence through nanotag donation to the handler and the retention of handler's DNA. In future we expect this approach to be used for other surfaces and conditions.

The Effect of Electrostatic Fingerprint Visualization on Integrated Ballistic Identification Systems

Visualization of fingerprint corrosion on spent brass cartridge cases by the application of a high electrical potential and conducting carbon powder is becoming an accepted method of fingerprint enhancement. However, to date, no examination has been made of any effect this technique has on ballistic identification. To resolve this, images of the breech face and firing pin marks were captured on six plated nickel and six brass primer cup spent cartridge cases. Three nickel and three brass cases were then subjected to the application of a potential of +2500 V for a period of 1 min. The remaining cases were additionally subjected to the application of carbon powder. These latter cases were then washed to remove all traces of powder. Each case was recaptured with the same ballistic identification apparatus and imaging procedure. None of the twelve cases showed any visual difference after the application of the potential or conducting powder.

Visualization of Latent Fingerprint Corrosion of Metallic Surfaces

Chemical reactions between latent fingerprints and a variety of metal surfaces are investigated by heating the metal up to temperatures of approximately 600 degrees C after deposition of the fingerprint. Ionic salts present in the fingerprint residue corrode the metal surface to produce an image of the fingerprint that is both durable and resistant to cleaning of the metal. The degree of fingerprint enhancement appears independent of the elapsed time between deposition and heating but is very dependent on both the composition of the metal and the level of salt secretion by the fingerprint donor. Results are presented that show practical applications for the enhancement to fingerprints deposited in arson crime scenes, contaminated by spray painting, or deposited on brass cartridge cases prior to discharge. The corrosion of the metal surface is further exploited by the demonstration of a novel technique for fingerprint enhancement based on the electrostatic charging of the metal and then the preferential adherence of a metallic powder to the corroded part of the metal surface.

Visualize fingerprints on brass after removal of secretions

The use of fingerprints left at the scene of a crime to identify an offender was first suggested in the nineteenth century,1, 2 and this branch of forensics continues to play an integral role in a wide range of criminal investigations.3 Sweat secretions deposited onto a surface leave an impression of the papillary ridge pattern of the finger, referred to as a latent fingerprint. Latent prints are not easily visible to the naked eye, and various techniques have been developed to enhance andmake them visible.4 In general, because these methods all require physical or chemical interaction between the enhancing reagent and fingerprint deposit, secretions must still be present. To tackle the problem of enhancing fingerprints on brass after removal of secretions, we have developed a technique that exploits a natural chemical reaction occurring between fingerprints and metal. Recent research has shown that this reaction, which involves corrosion, can change both the chemical and physical characteristics of the metal surface.5, 6 Unlike conventional treatments, our technique requires no enhancement of the fingerprint deposit prior to visualization. For our research, we selected brass because it is used to manufacture gun cartridge cases. Fingerprint enhancement on spent cases has attracted considerable attention, not least due to the problems it presents in terms of heat damage to the secretions during the firing process.7 We recently showed how fingerprints on brass cartridge cases that we left out for several days in open air at room temperature can still produce corrosion sufficient for visualization, even after they have been washed in warm water and detergent to remove the residue.8 Our technique required application of a potential to the brass (∼1,500V) followed by introduction of a conducting carbon powder (grain size ∼10μm). This process was facilitated by the use of a cascade developer (Foster and Freeman, Evesham, UK), an electrostatic detection device usually employed to enhance indented writing on paper, that coats tiny (∼400μm) spherical beads with the conducting powder. Figure 1. Fingerprint deposited on brass, left for five days, washed and then photographed (a) before and (b) after the application of a potential and a conducting powder.

Latent fingermark visualisation using a scanning Kelvin probe

The current state of the art in fingermark visualisation on metallic surfaces by a scanning Kelvin probe (SKP) technique is described. Latent eccrine fingermarks deposited on a range of polished and roughened metallic surfaces can be effectively imaged. Results are presented which show that the SKP technique is able to visualise fingermarks obscured beneath optically opaque soot films and retrieve ridge detail in instances where fingermarks have been physically removed (e.g. by rubbing with a tissue) from a metal surface. SKP Volta potential mapping of small, severely non-planar metal objects such as fired brass cartridge cases is demonstrated.

Small-scale explosivity testing

In the area of energetic materials testing, correlation of small- and large-scale test results is a frequently sought and seldom achieved goal. We have experimented using the cartridge test to obtain a relative ranking of the explosivity of energetic materials. The cartridge test attempts to detonate a 2 gram sample of energetic material confined in a .303″ brass cartridge case with a number 8 blasting cap. Violence of an event was judged by the weight of the main body of the casing remaining attached to the base after detonation.

Cartridge case deformation test

This paper describes a re-evaluation of a very sma11-scale explosives performance test which was first developed in the 1960's. The test uses a .303″ brass cartridge case both as charge container and witness piece, and has continued in intermittent use at the UK Forensic Explosives Laboratory to the present day. In the test a small quantity of the test material is loaded into the cartridge case and initiated by a No 6 detonator. A broad performance classification is obtained by inspection of the recovered cartridge case base, and more detailed comparisons of particular explosives may be obtained by weighing the recovered bases.

Development of Latent Fingerprints on Unfired Cartridges by Palladium Deposition: A Surface Study

Abstract Visualized fingerprints on unfired brass cartridge cases developed by a novel method of palladium deposition were examined by Auger electron spectroscopy (AES), scanning electron microscopy (SEM), and electron probe microscopy (EPMA). In spite of the strong contrast of colors between the ridges and the valleys of the developed images, which suggests a selective coating of palladium on the valleys, palladium was found to deposit onto both valleys and ridges. Lumps of organic material were scattered mostly along the ridges. The study suggests a model for the deposition of metals on brass cartridges on which sebaceous fingerprints were impressed.

Study of Brass Obturator Design for Combustible Cartridge Case for 105mm Tank Gun Ammunition

Brass cartridge case provides rearward obturation in the tank gun ammunition where the gun systedt has a sliding breech mechanism. In the case of semi-combustible cartridge case (SCCC) ammunition, obturation is provided by a smal1 metal stub. The mechanism of obturation and obturator design for kinetic energy and high explosive squash heat (HESH), SCCC ammunition of 105mm tank gun have been studied. The dynamic firing results for SCCC ammunition for 105 mm tank gun reveal height 115 mm provides perfect obturation. The ballistic performance of SCCC ammunition is comparable with that of the brass-cartridged round in the pressure range 150-450 MPa.

Firearm cartridge case comparison by graphite furnace atomic absorption spectrochemical determination of nickel, iron and lead

Graphite furnace atomic absorption spectrometry was used to determine the concentrations of nickel, iron, and lead in 26 different production lots of Winchester-Western cartridge case brass. In most cases, the measured elemental concentrations were found to be normally distributed within a lot, and the variables lacked any strong association. It was found that the concentrations of these three elements could be used as a basis for the comparison of individual cartridge cases to determine their provenance. Using the T-test with a significance level of 0.01, the frequency of obtaining a ‘true match’ and a ‘false match’ were found to be 98.1% and 0.43%, respectively. Additionally, a likelihood ratio was used to evaluate the extent to which provenance, or “common origin” among brass cartridge cases can be established.

Malfunction and failure analysis investigations of C26000 (Cu-30% Zn) brass cartridge cases

The C26000 alloy, containing 70% Cu and 30% Zn, is predominately used for cartridge case production and has an outstanding record of service. A multiple-step manufacturing process is employed to produce different microstructures in different sections of the cartridge case. The constant demands to increase performance have resulted in frequent revisions to the manufacturing process, and more stringent controls have been implemented in an attempt to produce a better product. Not surprisingly, however, failures and malfunctions are encountered in the “tryout” experiments. Studies indicate that failures in the head section can usually be traced to factors associated with gun design and propellent materials. Failures in the wall section are primarily stress-induced. Descriptions are given of the distinctive modes of failure in various sections of the cartridge case. The causes of failure and the remedies to prevent their recurrence are discussed.

Corrosion of New, Fired, 0.22-Caliber, Long-Rifle Brass Cartridge Cases Buried in Soil

Abstract An important exhibit at a double murder trial was a 0.22-caliber, long-rifle, rim-fire cartridge case, which was found on microscopic examination to have been fired in the 0.22 pump-action rifle belonging to the accused. It was found at the scene, more than 18 weeks after the murders, buried approximately 50 mm below the surface of a garden.

Centenaries, '62

GEORGE KYNOCH MOST PEOPLE know that ‘ICI’ means Imperial Chemical Industries and that this combine embraces many different industries (such as alkalies, explosives, paints, fibres) including a Metals Division at Birmingham. This was founded in 1862 as a small explosives factory at Witton, three miles from Birmingham. It was managed and later owned by George Kynoch (1834–91) and made percussion caps and cartridges. Caps were originally made to ignite the gunpowder in sporting and other guns, later the whole arrangement of explosive cap, gunpowder or other explosive, bullet or pellets was put together in a paper case called a ‘cartridge’. Later the container was stiffened cardboard for sporting guns and brass for rifles. The ‘solid‐drawn’ (i.e. drawn out from a blank by hammering) brass cartridge case was Kynoch's invention in the 1880's. He made cartridges for the British and all other governments, friendly or otherwise, who cared to buy them and pay for them (like Shaw's Andrew Undershaft). Later, Kynoch allowed his ambition to be a public figure (he was M.P. and Chairman of Aston Villa) to interfere with his devotion to his work as managing director. He was forcibly retired from the company he had founded and died in obscurity.