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A promising direction in barrel ballistics aimed at increasing the muzzle velocity of a projectile is the use of new propellants as an attached charge. This paper presents an experimental and theoretical method for determining the law of propellant combustion in a manometric experiment (in a closed volume). Within the framework of this method, a small number of experiments could be sufficient to determine a change in the law of combustion during the propellant burnout and depending on pressure. This method is demonstrated on the example of processing three experiments with model high-density propellant. The laws of combustion of high-density propellants, obtained in this study, can later be used to calculate the gas-dynamic parameters of a shot from a barrel system or a nozzle bomb (in a semi-closed volume) using these propellants. [ABSTRACT FROM AUTHOR]

The high recoil force of a high-power gun produces a strong impact on the carrier, which severely limits the application of the high-power gun mounted on vehicles. A gas-controlled side-jet gun was designed to reduce the recoil force, and the gas-solid transient flow in the bifurcated tube of the gun was studied. First, a one-dimensional two-phase interior ballistics model was established considering the gas-solid coupling between the propellant gas and the valve in the front gas tube. Then, the propagation of the rarefaction wave in the barrel was studied, and the flow field distribution in the bifurcated tube was obtained. Finally, the mechanism of recoil reduction was analyzed. Results show that the bifurcated two-phase flow model can be used to accurately analyze the effect of the gas-controlled side-jet gun's parameters on the projectile velocity and the recoil reduction efficiency. The projectile velocities of the gas-controlled side-jet gun and the traditional gun are 955.7 m/s and 960 m/s, respectively. The projectile velocity loss of the gas-controlled side-jet gun is less than 0.5 %. The recoil momentum of the traditional gun and the gas-controlled side-jet gun are 538.62 N·s and 336.68 N·s, respectively. The recoil momentum of the gas-controlled side-jet gun decreases by 37.49 %. Additionally, the single firing time of the gas-controlled side-jet gun (18.91 ms) is less than that of the traditional single-barrel gun (more than 60 ms). Therefore, the newly designed gas-controlled side-jet gun significantly reduces the recoil momentum without losing the projectile velocity and continuous firing mode. [ABSTRACT FROM AUTHOR]

Gunshot residues (GSRs) play an important role in forensic investigations of gun-related violence. The presence of GSRs has been described to help to identify the bullet entry area, as it was supposed not to be found at exit wounds. This report details the suicidal headshot of an 84-year-old male where unburned tube-like, cuboid and flake-formed powder particles have been found not only at the inside of the muzzle but also circular around the exit wound. With very short-barrelled weapons, it must be expected that part of the propellant charge leaves the barrel unburned behind the bullet. In contrast to that, the barrel length of the used weapon should lead to a complete burn-up of powder particles. The surprisingly large number of unburned powder particles present at the exit wound of the injury gave reason for further investigation to understand the underlying ballistic aspects and outlines the importance of having a close look at incidence scene photos during an investigation. [ABSTRACT FROM AUTHOR]

Launching large (> 1 g) well-characterized projectiles to velocities beyond 10 km s - 1 is of interest for a number of scientific fields, but is beyond the reach of current hypervelocity launcher technology. This paper reports the development of an explosively driven light-gas gun that has demonstrated the ability to launch 8-mm-diameter 0.36-g magnesium projectiles to 10.4 km s - 1 . The implosion-driven launcher (IDL) uses the linear implosion of a pressurized tube to shock-compress helium gas to a pressure of 5 GPa, which then expands to propel a projectile to hypervelocity. The launch cycle of the IDL is explored with the use of down-bore velocimetry experiments and a quasi-one-dimensional internal ballistics solver. A detailed overview of the design of the 8-mm launcher is presented, with an emphasis on the unique considerations which arise from the explosively driven propellant compression and the resulting extreme pressures and temperatures. The high average driving pressure results in a launcher that is compact, with a total length typically less than a meter. The possibility to scale the design to larger projectile sizes (25 mm diameter) is demonstrated. Finally, concepts for a modified launch cycle which may allow the IDL to reach significantly greater projectile velocities are explored conceptually and with preliminary experiments. [ABSTRACT FROM AUTHOR]

The energetic potential of bimolecular crystals (BMCs) containing CL-20 as components of solid composite propellants (SCPs) was investigated. The experimental and calculated values of the standard enthalpies of formation are reported. The maximum heats of explosion, which correlate with the impact sensitivity, were calculated. The specific impulse values and the densities of SCPs based on an active binder, aluminum, and oxidizer (BMC + a small portion of ammonium dinitramide) were evaluated. [ABSTRACT FROM AUTHOR]

This paper reports thermolysis of diaminoglyoxime (DAG) as a ballistic modifier, and its effects on the thermal behaviors, non-isothermal decomposition reaction kinetics, and burning rates of the homogeneous double-base propellant formulations. Thermal analysis studies were performed by thermogravimetric analysis and differential thermogravimetry (TG-DTG) and differential scanning calorimetry techniques. According to the resulted data, it was found that DAG could change the thermal decomposition mechanism function, thermokinetic parameters and kinetic equation of the propellants. Evaluation of DAG as a ballistic modifier in double-base propellant formulations indicated that it brings down the pressure index to 0.068 compared to 0.24 for the control composition in the pressure range 5-7 Mpa. The results showed that the main exothermal decomposition reaction of the propellant sample in the absence of DAG has the mechanism function of $$ f(\alpha ) = \frac{3}{2}\left( {1 - \alpha } \right)^{4/3} [\left( {1 - \alpha } \right)^{ - 1/3} - 1]^{ - 1} $$ and the kinetic equation of $$ {\raise0.7ex\hbox{${{\text{d}}\alpha }$} \!\mathord{\left/ {\vphantom {{{\text{d}}\alpha } {{\text{d}}t}}}\right.\kern-0pt} \!\lower0.7ex\hbox{${{\text{d}}t}$}} = 1.60 \times 10^{17} \left( {1 - \alpha } \right)^{4/3} [\left( {1 - \alpha } \right)^{ - 1/3} - 1]^{ - 1} e^{{ - 2.21 \times 10^{4} /{\text{T}}}} $$ , while modified propellant with DAG has a different function mechanism and kinetic equation as following: $$ f(\alpha ) = \frac{5}{2}\left( {1 - \alpha } \right)\left[ { - { \ln }\left( {1 - \alpha } \right)} \right]^{3/5} $$ and $$ {\raise0.7ex\hbox{${{\text{d}}\alpha }$} \!\mathord{\left/ {\vphantom {{{\text{d}}\alpha } {{\text{d}}t }}}\right.\kern-0pt} \!\lower0.7ex\hbox{${{\text{d}}t }$}} = 9.28 \times 10^{40} \left( {1 - \alpha } \right)\left[ { - { \ln }\left( {1 - \alpha } \right)} \right]^{3/5} e^{{ - 4.66 \times 10^{4} /{\text{T}}}} $$ , respectively. [ABSTRACT FROM AUTHOR]

A laboratory gun that uses compressed gas as its propellant was designed and tested for the study of small projectiles traveling in soils with initial velocities ranging from 50 to 200 m/s. The gun employed the use of air or helium with an electrically triggered, pneumatically piloted, solenoid valve. The triggering system was designed to provide remote activation. A photo gate speedometer was utilized to measure the exit velocity of each projectile. Details of the electro-pneumatic control system are presented in this paper along with the design of the gun assembly and its subsystems. The effects of different design parameters, including muzzle length, projectile mass, propellant type, and volume of compressed gas utilized, on projectile velocity were investigated. Statistical analysis of the gun performance is presented. The gun is currently being used to visualize the fundamental physics of rapid earth penetration in soils, using transparent soils. [ABSTRACT FROM AUTHOR]