Experimental Investigation of the Bullet-proof Properties of Different Kevlar, Comparing .22 Inch with 9 mm Projectiles

Abstract

Background: Results of an experimental study are given involving high-impact ballistic tests using .22 inch diameter ammunition (commonly known only as .22 ammunition) with the target set up as a combination of different numbers and weights of Kevlar layers. These experimental tests are conducted as literature indicating that the .22 projectiles are not as effective as with larger calibre ammunition. Present work is part of a research study to assess the safety limits of Kevlar layers of different weights against various calibre projectiles. Objective: The objective is to obtain test data to determine the number of Kevlar layers and weights needed for the design of safe bullet proof vests capable of stopping various size ammunition. In the present study, results are given for .22 inch ammunition, which provide data on the characteristics of high-speed ballistic penetration of .22 bullets into Kevlar layers and stopping distances in gel/Kevlar combinations. Methods: Tests were performed with Kevlar fabrics of different weights of Gram per Square Meter (GSM) to provide a comparison among different Kevlar fabrics as well as with different number of Kevlar layers. The tests were conducted with the use of a chronograph in a controlled test environment. The penetration depth in ballistic gelatine was recorded. Results: The results identify the number of layers of Kevlar required to stop a .22 projectile and the relationship between the different layers and weights of Kevlar materials. The results of the .22 projectile penetration are compared with those of different 9 mm Parabellum projectiles to assess the effect of different size ammunition on the bullet-proof capabilities of Kevlar. Experimental data on the penetration depths of different types of bullets into the gel/Kevlar combinations are presented using various graphs. Conclusion: The .22 projectiles perform similar penetration depths compared to that of 9 mm projectiles, and therefore cannot be considered as ineffective ammunition as literature has indicated.