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This report relates to the discovery and development by the authors of armor designs using certain elastomers applied as coatings to the front side of rigid substrates, to increase the ballistic and blast performance of armor. This has led to much activity intended to optimize and exploit the technology for various applications, both military and civilian. Since armor improvements of even a few percent are substantial, quantifying the performance of armor materials requires high accuracy. Herein we describe test methods and analyses useful in achieving measurements of sufficient quality. Since the optimal design of any armor, conventional or advanced, depends on the threat (i.e., the nature of the projectile and its mass and energy; single- versus multiple-hit defeat), we describe how performance attributes can be quantified and valid comparisons made between different armor designs.

An efficient method was needed to perform ballistic testing using 0.30-cal. Fragment Simulating Projectiles at or near subsonic velocity in order to screen new resin systems for advanced composite/ceramic armor scaled-down test coupons. This technical note outlines the custom gun system and testing methods developed to enable this ballistic testing.

This paper describes the internal, external, and terminal ballistics of the 30-06 rifle cartridge. With cartridge case capacity of 68-70 grains of water and operating pressures up to 60,000 psi, the 30-06 launches 110-220 grain bullets with muzzle velocities between 3400 fps and 2400 fps, respectively. Low-drag bullets are available which make the 30-06 an effective and capable choice for target and anti-personnel use out to 1000 yards, but longer range applications are challenging due to the sonic transition. With an appropriate bullet choice, the 30-06 penetrates a variety of commonly encountered barriers. It also penetrates soft body armors and can deliver significant wounding effects even when stopped by hard body armor. At shorter ranges, wounding effects in human and deer-sized living targets are impressive and yield rapid incapacitation.

The experiment reported in this article addresses whether polishing a rifle bore reduces the aerodynamic drag of bullets. It was hypothesized that by polishing a rifle bore the aerodynamic drag of bullets would be reduced because a smoother bore would result in smoother rifling marks and thus lower drag. A Remington 700 5R Mil-Spec chambered in 300 Winchester Magnum was used. The bullets used were a 155.5 grain Berger Fullbore Boat Tail and a 125 grain Nosler Ballistic Tip with near and far velocities measured with chronographs at 15 and 315 feet. G1 and G7 ballistic coefficients were calculated using the JBM online ballistics calculator including environmental conditions measured with a Kestrel 4500 Pocket Weather Tracker. These measurements did not support the hypothesis; in fact, the velocity losses were greater over the 300 foot chronograph separation and the ballistic coefficients were smaller after polishing the rifle bore. This suggests that polishing the rifle bore actually increased resulting aerodynamic drag on the bullets

This report documents the theory and use of the BOOM computer program. BOOM is an exterior ballistics simulation program specifically designed to predict atmospheric flight of smart projectiles. The software contains a projectile dynamic model coupled to an open structure flight control system. The code can be run on PC, Unix, or Mac systems.

An efficient method was needed to perform ballistic testing using the 0.22-cal. fragment-simulating projectiles (FSP) at low subsonic velocities in order to evaluate very thin lightweight composite and metallic materials at around 1 lb/ft2 areal density. This technical note outlines the custom gun system developed to enable this ballistic testing.

Recent requirements for hypervelocity projectile launch for strategic U.S. Army missions have led to the proposal of a variety of gun propulsion systems. Among these systems are those that utilize solid propellant along with electrothermal-chemical (ETC) augmentation. Advanced solid propellant systems with complex grain geometry and loading configuration are also being investigated. In response to this need, the U.S. Army Research Laboratory (ARL) has, for a number of years, engaged in the study of solid propellant ignition using a hot, low molecular-weight plasma generated by ETC means. In addition, ARL is developing an ETC modeling capability using the next-generation interior ballistics code, NGEN, and a series of experimental studies in a ballistic simulator to generate code validation data. The current report demonstrates progress for application of the NGEN code to solid propellant, direct-fire gun systems in which various propellant configurations (i.e., grains and disks) are combined into a single charge in order to obtain higher-loading densities. The charge is ignited using the efflux from an ETC plasma capillary made of polyethylene. Comparison with pressure data measured in a 25-mm ballistics simulator, filled with disks of JA2 propellant as the main charge and a small amount of inert grains as filler, provides validation of the NGEN model with respect to the representation of the plasma efflux from an ablation capillary, into the chamber, and around propellant disks.

Recent requirements for hypervelocity projectile launch for strategic U.S. Army missions have led to the proposal of a variety of gun propulsion systems. Among these systems are those that utilize solid propellant along with electrothermal-chemical (ETC) augmentation. Advanced solid propellant systems with complex grain geometry and loading configuration are also being investigated. In response to this need, the U.S. Army Research Laboratory, in cooperation with Paul Gough Associates, is developing the Next Generation Interior Ballistics model, NGEN. The goal of this project is the development of an advanced interior ballistics model for use in the design and investigation of both indirect-and direct-fire gun propulsion systems. The current report demonstrates progress for application of the NGEN code to solid propellant, direct-fire gun systems in which various propellant configurations (i.e., grains and disks) are combined into a single charge in order to obtain higher-loading densities. The charge may be ignited using either a conventional (Benite) or an ETC plasma capillary. These notional charges are being investigated to determine code performance and assess the need for code upgrades, as well as to investigate propellant ignitability with Benite and plasma sources. Comparison with pressure data measured in a 25-mm ballistics simulator, filled with inert disks and grains, provides validation of the NGEN model with respect to the representation of the plasma efflux from an ablation capillary, into the chamber, and around propellant disks.

The U.S. Army is exploring a variety of armament propulsion options for indirect- and direct-fire weapons to be employed in the legacy force and for the Future Combat System (FCS). Development of propelling charges for these weapons requires state-of-the-art physics-based modeling codes. The gun propulsion-modeling environment has traditionally been one in which independently developed and upgraded computer codes were used to analyze different propulsion techniques. with no single maintainable code able to evaluate several candidate system. This situation rendered comparison of ballistic performance for various weapon options cumbersome and inconclusive. In direct response to this situation. the U.S. Army Research Laboratory (ARL) has developed a "next-generation" computer scaleable. three-dimensional, multi-phase, computational fluid dynamics code for armament propulsion (interior ballistics) modeling.

A shaped charge device was designed from a charge with a four-sided pyramid as the liner. Devices of this nature were first studied by Geiger and Honcia in 1977 and relegated to the area of interesting concepts, but without application. The current study represents probably the first numerical simulations of this charge, including parametric variations of the altitude of the pyramid and the initiation mode of the explosive. The numerical simulations were performed using the CTH hydrocode (shock physics code) developed by Sandia National Laboratories. The liner was made of copper, and the wall thickness of each isosceles triangle comprising the pyramid was identical. The multiple interacting jets provide a wide area of coverage that implies that the device may be useful as a multidirectional cutting charge. A multidirectional charge may be useful for certain applications in the mining, oil well completion, demolition, or military fields.

A principal challenge faced by the U.S. Army TACOM-ARDEC Benet Laboratories in the design of armaments for lightweight future fighting vehicles with lethality overmatch is mitigating the deleterious effects of large caliber cannon recoil. The sonic RArefaction waVE low recoil guN (RAVEN) is a novel invention to dramatically reduce the gas momentum contribution to recoil with absolutely no reduction in me ballistic efficiency of launch. This technology is being investigated as part of the future combat vehicle armaments program conducted at Picatinny Arsenal, NJ, and Watervliet Arsenal, NY.

In recent years, substantial improvements in the performance of solid propellant guns have resulted from the development of higher energy propellants, higher loading density propellant charge configurations, and propellant geometries and concepts that have provided the progressively increasing gas generation rates required to efficiently use available increases in total energy. Unfortunately, these same features also typically lead to increases in ammunition vulnerability to enemy threats. Coupled with the current interest in much lighter fighting vehicles, the need for ammunition with reduced rather than increased sensitivity is obvious. This report describes the development of a new approach in the U.S. Army to address propellant energy/ performance and sensitivity/vulnerability as a single set of critical design requirements, to be addressed concurrently from the very beginning of the new energetic material research and development cycle. Some elements of this work were presented in abbreviated form at the 19th International Symposium on Ballistics in Interlaken, Switzerland in May 2001.

A sabot launched spin-stabilized training projectile is being developed by the U.S. Army for the 25mm cannon. The training projectile is required to ballistically match the present service projectile. The ballistic match requirements are stringent and the transitional ballistics, aeroballistics and jump characteristics of the training projectile must be controlled to satisfy the requirements. This report presents the results of a series of tests which were designed to evaluate the transitional ballistics, aeroballistics and jump characteristics of the training projectile. The same tests are performed on the service projectile to provide a baseline for evaluation of the ballistic match. It was found that the training projectile did satisfy the maximum range requirement of 8000 meters. The jump characteristics of the training projectile and the service projectile are different enough to cause concern about the ability of the training projectile design to meet the center of impact requirement on the target. Keywords: Training ammunition, Spin-stabilized ammunition.

This report summarizes the development to date of a 1/4-scale launcher designed to launch a 7.2-kg model at a 6.1 km/sec in full scale. The hybrid launcher design principles are reviewed. Projected performance shows launch masses within soft-launch constraints that are 3 to 4 times larger than possible by using a conventional two-stage launcher. The results of component development tests leading to the subscale demonstration are presented. The importance of tungsten liners for obtaining the projected performance is emphasized, and the results of liner bond developments are described. (Author)

A series of four reverse ballistics tests were performed on two different types of earch penetrators at various impact angles and obliquities. The objective of this test series was to provide an improved and expanded strain and acceleration data base for critical impact environments on earth penetrators. (Author)

This report documents an investigation of the feasibility of a hybrid hypervelocity launcher. Included are evaluations of: (1) the thermodynamic performance of the working medium, (2) the ballistic cycles necessary to achieve the desired projectile muzzle velocities, (3) possible loss mechanisms which can degrade ballistic performance, and (4) material response to predicted heat loads. (Author)

An analytical model for the linearized velocity-coupled combustion response function was developed. The model combines elements of response to velocity perturbations, pressure perturbations, and compositional perturbations due to the heterogeneity of composite propellants. The important effects of AP size distribution are accounted for in terms of effects on ballistics properties and in terms of periodic fluctuations in propellant composition. Properties of the response function have been calculated theoretically over a range of the governing variables. There are two facets of the crossflow problem: the response to velocity perturbations, and the effect of crossflow velocity on the various response elements. The crossflow mechanism is heuristically based upon the so-called 'Soderholm erosive burning law,' but which has been given physical significance in the theoretical work of Kuo. Significant results are described. In addition, the triggered non-linear instability experiments performed at CARDE were reviewed and shown to depend upon the achievement of a formulation-dependent critical velocity in the rocket motor. Progress was made in the measurement of the pressure-coupled response functions of propellants formulated to seek out the effects of AP particle size. Progress was made toward formulating a high frequency combustion response model applicable to nitramine/minimum-smoke propellants.

Studies were directed at the deflagration of heterogeneous, condensed media. Relations among ballistic properties were studied; generalized relations were derived and existing relations for testing the consistency of data from ballistic test motors were shown to be general to small error; errors in the recent literature were corrected. A new device for characterizing the ballistic properties of condensed media at high pressure with strands was devised and explored analytically. Self-pressurized constant pressure operation was shown along with capability to control the pressure level with a simple bang-bang control system. Special configurations to provide direct little difference measurements of ballistic sensitivities were presented. The Deur/Glick serial sandwich model for heterogeneous propellant combustion was modified to overcome the 'continuation' problem implicit in that model. Results showed ignition delays of correct magnitude and, with physical reasoning, demonstrated that the ZN methodology cannot be applied to heterogeneous propellants in its present form. Keywords: Solid rocket propellants, Solid propellant rocket engines.

Liquid propellants have been the focus of periodic research efforts since just after the Second World War. Early efforts centered on the mechanically simple bulk loaded liquid propellant gun. A large number of experimental gun firings were conducted, and semi-quantitative models of the bulk loaded interior ballistic process were developed. However, the ballistic control required of a practical gun system has been achieved. In contrast, the regenerative liquid propellant gun has demonstrated the required ballistic control, but at the expense of mechanical complexity heretofore unknown in gun systems. Nevertheless, the regenerative liquid propellant gun may provide the mechanism for the development of a practical weapon system based on a liquid gun propellant.

A qualitative description is presented of the effect of chambrage, the increase in cross-sectional area from the barrel bore to the propellant chamber. The effects of the other fundamental factors which determine the pressure behind a projectile are discussed including the propellant burning, the presence of the breech end, and the accelerating projectile motion. The description is given in terms of the rarefaction and compression impulses which are present in the propellant gas during the firing of a gun. In ballistic calculations, chambrage is treated by assuming that the actual chamber can be replaced by an equal volume chamber of cross-sectional area equal to that of the bore. This method of treatment may be in error. The possible size of this error is indicated by a calculation of the muzzle velocity of a gun with an optimum condition of chambrage which is approached by a gun with either a large, well- shaped chamber or with a propellant burning at the proper rate in a smaller chamber. The muzzle velocity of the optimum chambrage gun is shown to be as much as 28% greater than that of the comparable constant-diam gun.

Included in this report are studies of ballistic trajectories for a point mass moving in three degrees of freedom relative to a rotating oblate earth. All trajectories are launched from Vandenberg AFB, California to points of interest in the Pacific Missile Range. A running account of the position, forces exerted on the vehicle, and atmospheric information is given throughout the trajectory with a more detailed account given from reentry into the atmosphere to impact. Vernier Engine Cut-Off (VECO) occurs at the same range from Vandenberg $

The object of this investigation was to determine, by wound ballistics tests, the most efficient bullet of a series of .22 caliber full patch rounds.

This report describes a field experiment conducted to study the feasibility of using only inertial and aerodynamic forces to deploy a cluster of dense, inert, low-drag submissiles into a narrow conical pattern subsequent to burnout of a high-acceleration rocket which has accelerated the warhead to a velocity in the low hypersonic region.

This report was prepared in response to a request by personnel of Lincoln Laboratory to have available a detailed description of the flow field of a spherical pellet, at a specified ballistic range condition in argon. A similar calculation of flow field details was performed for an air atmosphere at the aforementioned velocity and pressure.

The tests reported here were conducted to determine the effects produced on the ballistics of a liquid monopropellant round by advancing the point of venting of the primer within the propellant column. The tests were conducted with two case configurations in which the L/D ratios of the propellant columns were approximately 3.4 and 5.0. As the point of venting was advanced, muzzle velocity increased in rounds with the L/D ratio of 5.0, but decreased in those with the L/D ratio of 3.4. The amount of unburned propellant remaining in the case after firing increased in both case configurations. In both configurations, the pressure curves were transformed from curves with two distinct pressure peaks, through stages approximating plateau configurations, to curves with one well defined pressure maximum.

Development of the XM152 red marker warhead and XM153 yellow marker warhead for the 2.75 inch Folding Fin Aircraft Rocket (FFAR) was successfully accomplished in eight weeks. This report presents the results of static tests conducted at Picatinny Arsenal and ballistic tests at other installations during this program and in related investigations.

Revised overpressure curves for liquid oxygen RP-1 missile explosions have been developed. The overpressure is presented as a function of the total propellant weight and the distance from the explosion.

Closed-breech interior-ballistic equations were modified for predicting the performance of reactionless launchers. Test firings were made using two reactionless launchers of the Davis Gun type. Direct and high-low launchers were considered. The test firing data was compared with the curves obtained from an analog computer. Using the differences noted, certain factors of the original equations programmed into the computer were varied in order to bring the computer curves into close agreement with actual test results. These factors included heat loss coefficient, initial charge burnt, and in the case of the high-low gun the effective mean impetus of the propellant during the ballistic cycle. It was concluded that the knowledge gained with the computer can be used to optimize the performance of reactionless systems.

The report describes a method of computing ballistic trajectories of projectiles subjected to lateral drift as a result of crosswinds.

Vertical Wind on Tactical Rockets and Artillery Shells. Research and development technical rept.,Engebos,Bernard F. ;DA-1-T-061102-B-53-A1-T-061102- B-53-A-18ECOM5467(*projectiles, impact prediction), (*guided missile ranges, *wind), rockets, rocket trajectories, projectile trajectories, meteorological phenomena, drift, exterior ballistics Vertical wind effects on the Honest John (M50) tactical rocket and the 155 millimeter howitzer projectile are discussed. Theoretical trajectory simulations were calculated with quadrant elevations of 200, 400, and 800 mils. It was found that the vertical wind component can play a significant role on the impact points of an Honest John fired at a low angle and a 155 howitzer fired at a high angle. With the aid of vertical wind measurements, more accurate impact points could be obtained.

This report describes the testing of nine Frankford Arsenal XM12 rocket catapults with the Douglas Aircraft RB66 airplane. The results show that the performance of the XM12 catapult was satisfactory and that it will safely eject the designated seat-man system throughout the operational speeds and altitude range of the B-RB66 series aircraft.

A general parametric and preliminary design study has been completed defining the potential capabilities of rocket boosted artillery projectiles for high altitude probes when fired from existing gun systems. The study indicates that single stage vehicles fired from a 5 inch gun can lift a 10-pound payload to 650,000 feet and a 50-pound payload to 250,000 feet. Two stage vehicles fired from a 16.4 inch gun can lift payloads of 100 pounds to altitudes greater than 400 miles. A 4.5 inch rocket boosted artillery projectile, sub-calibered in the 7 inch gun, was designed for a specific requirement for delivering a 20- pound payload to an altitude of 500,000 feet with a minimum impact dispersion; however, this does not represent the maximum payload or altitude possible for probes fired from the 7 inch gun. Comparisons were made between long burning sustainer designs with zero ignition delay and short burning booster designs with an optimum ignition delay. The comparisons indicated that both types will, for similar payloads and propellant weights, reach approximately the same altitude. A brief discussion of the orbiting capabilities of rocket boosted artillery projectiles is presented.

The method of calculating the behavior of a projectile propelled by a pre-burned propellant in a chambered gun is reviewed. The influence of gas in front of the projectile in the barrel is discussed, as is the procedure to take account of gas frictional and heat-transfer effects. The method of calculation by hand of the perform-ANCE OF TWO-STAGE GUNS IS THEN OUTLINED. Some results obtained from an electronic computing machine are compared with experimental results.

Numerical integration methods for solution of the system of differential equations found in ballistic rocket trajectory programs are discussed. The general discussion entails the explicit formulas of Runge-Kutta and predictor-corrector methods and their errors, and a brief description of other methods that could be employed.

The book presents brief information on the development of the principles of firing, on modern weapons of rifle small units, on explosives and their properties, and information on interior and exterior ballistics; an understanding of the essense of aiming is presented and the design of various sights is given; questions on the practical significance of the shape of the trajectory and the action of shells (bullets) on a target are presented; the basic questions from the theory of probability and the theory of errors, dispersion, hit probability, and target destruction are illuminated.

The results of an exterior ballistics test of the M193 ball projectile when launched from the M16A1 rifle are presented and discussed. Rifles with twists of 1 turn in 12 inches and 1 turn in 14 inches were used in the tests. Data were gathered from test firings at the small Aerodynamics Range and the Transonic Range of the Ballistic Research Laboratories and from a temporary range set up in the Climatic Hangar at the Eglin Air Force Base, Florida. Tests at Eglin were conducted at air temperatures ranging from +125 deg. F to -65 deg. F. (Author)