Product development of a handguard : For AK4 weapon system/Heckler & Koch G3

Abstract: The AK4 rifle serves as the primary weapon for the Home Guard, an integral part of the Swedish Armed Forces. Introduced in 1964, the AK4 is the Swedish version of the Heckler & Koch G3 and functions as a fully automatic assault rifle. Among its components, the handguard holds significant importance, providing stability, improving accuracy and control, and protecting the user from heat generated by the barrel. Recognizing the need for optimization, an employee from the ALTEN Group, possessing military experience and expertise in the AK4, launched a project to enhance the ergonomics and versatility of the handguard in a cost-effective manner. This initiative stems from the excessively high cost of commercially available handguards, making them financially unviable for replacing the original handguard of every AK4 used by the Home Guard personnel. This project aims to design and develop a next-generation handguard for the AK4 rifle that addresses the current limitations of the existing handguard. The primary focus is improving the shooter’s performance by establishing a comfortable shape of the handguard, reducing the weight, and enhancing its compatibility with accessories. Additionally, the aim is to ensure the handguard is cost-effective for mass production and meets the requirements set by the Swedish Defense Materiel Administration. To achieve the aims, interviews and a comprehensive user testing study was conducted, collecting quantitative data in the form of participant ratings and rankings for different design concept while also gathering qualitative data through participant feedback that highlighted specific design features contributing to comfort. Additionally, a systematic material selection process was performed, involving the analysis and ranking of various materials based on properties such as weight, price, and specific mechanical properties. Furthermore, the manufacturing analysis relied mainly on conversations with industry experts possessing expertise in the field of plastic manufacturing. Upon conducting a detailed analysis, it has been determined that the ideal configuration for the final product is an octagonal shape. After careful evaluation, Polyamide 6 reinforced with 30% glass fibers has emerged as the most suitable material choice for the handguard. This material had the optimal balance between mechanical properties, thermal performance, durability, cost-effectiveness, and environmental impact. To produce 50,000 handguard units, the recommended manufacturing method was injection molding due to its compatibility with mass production and the advice received from industry experts. Considering the design and selected material, a substantial number of the requirements outlined by FMV could be fulfilled by conducting both theoretical analyses and practical experiments.