# Ammunition and Mechanical Efficiency in Firearms Mechanical efficiency refers to how effectively a firearm converts ammunition energy into reliable operation. 9mm ammo is optimized for efficient energy transfer in compact handgun systems. .223 ammo is designed for efficient gas system operation in semi-automatic rifles. .308 ammo balances mechanical efficiency with high-... https://bulkammotogo.com/product-category/223-remington-ammo/