 Like the 5.45×39mm cartridge, 9×39mm SP-5 features an airpocket in the tip, which increases its tendency to yaw or "keyhole" upon impact, thus increasing soft tissue damage in human targets, and also the armor-piercing SP6 cartridge are more effective against light armored, vehicle, or light barrier targets, although neither of those are imported into the USA.SP-5 (7N8) - The SP-5 (СП-5) (SP