The present invention relates to a non-lethal projectile for a firearm composed of a novel, soft and elastic, composite material comprising a polymeric organic matrix and a pulverulent metallic filler, with a relative density of between 4 and 22, dispersed in the polymeric matrix. The composite material has a relative density of between 1.0 and 2.9 and a Shore A hardness of between 2 and 30. The polymeric organic matrix is a crosslinked polybutadiene comprising polybutadiene chains with a mass of between 500 and 10,000 connected by bridges. The projectile according to the invention makes it possible to neutralize an animal or a person without endangering his life and without inflicting serious injuries, even when firing at a short range of less than 5 m.