A regenerative braking system , comprising: a barrel comprising a bore ; a circuit including a plurality of electrically conductive components distributed along a length of the bore ; a projectile comprising at least one of a conductive material or a magnetic material magnetically coupled to the electrically conductive components when the projectile is moving along the length of the bore ; and wherein: the circuit is configured to store energy generated from an electric current induced in the electrically conductive components when the projectile moving along the length of the bore causes a magnetic interaction between the electrically conductive components and the at least one of the magnetic material or the conductive material , and the magnetic interaction is configured to cause braking of the projectile , characterized in that the regenerative braking system further comprises a connector configured to attach the barrel to a muzzle of a firearm , wherein the projectile comprises a bullet configured to be fired into the barrel from the muzzle , wherein: the barrel comprises a vent positioned forward of the electrically conductive components , and wherein the vent is configured to vent an exhaust from the firearm . a barrel comprising a bore ; a circuit including a plurality of electrically conductive components distributed along a length of the bore ; a projectile comprising at least one of a conductive material or a magnetic material magnetically coupled to the electrically conductive components when the projectile is moving along the length of the bore ; and wherein: the circuit is configured to store energy generated from an electric current induced in the electrically conductive components when the projectile moving along the length of the bore causes a magnetic interaction between the electrically conductive components and the at least one of the magnetic material or the conductive material , and the magnetic interaction is configured to cause braking of the projectile , characterized in that the regenerative braking system further comprises a connector configured to attach the barrel to a muzzle of a firearm , wherein the projectile comprises a bullet configured to be fired into the barrel from the muzzle , wherein: the barrel comprises a vent positioned forward of the electrically conductive components , and wherein the vent is configured to vent an exhaust from the firearm . the circuit is configured to store energy generated from an electric current induced in the electrically conductive components when the projectile moving along the length of the bore causes a magnetic interaction between the electrically conductive components and the at least one of the magnetic material or the conductive material , and the magnetic interaction is configured to cause braking of the projectile , characterized in that the regenerative braking system further comprises a connector configured to attach the barrel to a muzzle of a firearm , wherein the projectile comprises a bullet configured to be fired into the barrel from the muzzle , wherein: the barrel comprises a vent positioned forward of the electrically conductive components , and wherein the vent is configured to vent an exhaust from the firearm . <EOS>