The present invention relates to the field of military technology, and more particularly to an automatic firearm. Said firearm consists of a receiver, a barrel, a bolt carrier and a bolt, a bumper spring on the bolt carrier, a recoil spring between the bolt carrier and the rear wall of the receiver, a trigger mechanism, an ammunition feed mechanism, sighting equipment, a device for locking the bumper spring in a compressed state caused by the bolt carrier striking the front wall of the receiver or the barrel or the bolt via the bumper spring, and a mechanism for synchronizing the release of the bumper spring with the firing of a shot. Additionally, the firearm can be provided with an additional bumper spring between the bolt carrier and the rear wall of the receiver, and a lever for compressing and subsequently releasing said additional bumper spring in case the manual reloading in order to impart additional kinetic energy to the bolt carrier for the forward movement thereof, wherein said lever can be combined with a recharging handle. Additionally, the firearm can be provided with an additional device for locking the bumper spring in a compressed state caused by the bolt carrier striking the rear wall of the receiver via the bumper spring, and a lever for compressing and subsequently locking the bumper spring during the rearward movement of the bolt carrier in the case of manual reloading, wherein said lever can be combined with a recharging handle. The technical result provided by the above combination of features is the creation of a firearm having an inertial automatic loading system that functions reliably and consistently due to the increased reloading system working speeds and increased recovery of recoil energy.