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In the search of a new weapon for combat in short range, it is proposed the use of a new experimentally designed 7.62 mm calibre ammunition with a lighter weight (caseless-coreless). This can be used in carbine assault rifles with short barrel or pistols. In this work, the compressible gases flowing through the gun barrel caused by the proposed ammunition were experimentally and numerically analysed. The Large Eddy Simulation was used for the numerical simulation, considering a compressible and turbulent flow, with the chemical species transport model and a complete conversion of the propellant reaction. Variations in pressure and temperature were compared with the results obtained from a conventional 7.62 mm full metal jacket (FMJ) ammunition. Results of ballistic experimental tests and numerical simulations were similar than those of the 9 mm x 19 mm FMJ ammunitions, showing feasibility for the development of new weapons intended for operations of short range shots.

A manufacturing method is proposed using two conventional methods, film insert molding and compression molding, to obtain rectangular of the size of 250 × 35 × 2.5 mm specimens of polycarbonate reinforced with 4% mat fibers glass with orientations 90/0° and ±45°, to investigate, disorientation of the fibers. A Finite Element Method was performed, using Moldflow to determine initial conditions to predict the behavior of the polymer during the compaction stage and then manufacture the mold. Physical tests were performed using a conventional injection machine, based on the results previously obtained in the simulation. Woven fiberglass did not require a chemical treatment previously to achieve adhesion between the two types of polycarbonate. Specimens of polycarbonate reinforced at 0/90° and ±45° orientation have demonstrated small fiber orientation distortion. For the case of 0/90° specimens, the maximum deviation is show in the specimen with 2.58° which represent a misalignment cause by compression stage which also happened in 0° where the maximum standard deviation is 0.98°. Measurements for the +45° fibers, the standard deviation is 2.60° and 2.23° for −45°. According to ASTM D3039, the deviation of fiber, are within the tolerance to be characterized and obtain the mechanical properties. POLYM. ENG. SCI., 59:E372–E379, 2019. © 2019 Society of Plastics Engineers

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