The Inertia FRONT DRIVE® System is the heart of the Franchi family of semi-automatic firearms and relies upon one of the basic laws of physics: The Law of Inertia. In physics The Law of Inertia states that an object at rest tends to stay at rest; that object, in the Inertia FRONT DRIVE® System, is the free-floating bolt. When the gun is fired all of the fixed parts of the gun are propelled rearward by the gun’s recoil. In the Inertia FRONT DRIVE® System, all of the gun parts are fixed except one: the free-floating bolt. Between the free-floating bolt and the rotary locking head is a short, very stiff inertia spring. When the gun fires, the bolt briefly holds its position as the fixed parts move to the rear, causing the inertia spring to be compressed. As the shot charge leaves the barrel and the rearward force of the gun diminishes, the compressed inertia spring throws the bolt rearward with sufficient force to unlock the rotating bolt head, eject the spent shell and recock the hammer. The recoil spring then returns the bolt, which travels forward picking up and chambering another shell and locking the rotating head back into place. With the Inertia FRONT DRIVE® System, the bolt weight and inertia spring power are sufficient to cycle light loads and they have no choice but to function on all heavier loads - it’s the law of physics.

Inertia FRONT DRIVE® System
As the bolt assembly moves into battery, the locking head pin moves along a curved track in the bolt body to rotate the steel bolt head into engagement with the steel barrel extension. The cartridge drop lever is down, its red dot indicating the gun is cocked.
When the trigger is pulled, the gun fires and every part of the shotgun except the bolt body moves rearward. The curved track in the bolt body, which is moving forward relative to the rest of the gun, presses against
the locking head pin, turning the bolt head even tighter into the barrel extension. At the same time, the inertia spring is compressed between bolt head and body. The cartridge drop lever moves up, allowing a shell to move from the magazine to the carrier.

Near the end of the recoil cycle, chamber pressure drops to a safe level and the gun’s rearward motion slows. The heavy inertia spring then thrusts the bolt assembly rearward, unlocking the rotating bolt head, extracting the spent shell from the chamber and pulling it against the ejector.
As the empty shell exits the receiver, the energy of the moving bolt assembly recocks the hammer and compresses the recoil spring on the magazine tube. The recoil spring then thrusts the bolt assembly forward, lifting the oncoming shell into position and chambering a fresh cartridge. The gun is ready to fire again…in a fraction of a second!