(In Case You Hadn’t Noticed)

The most popular 12 gauge shotgun at Scuttlebuck Lodge over the past 25 years has undoubtedly been the Beretta gas-operated semi-automatic.  Gas-fed means simply that a portion of the high-pressure propellant gases are bled off to operate the action.

  • How It Works
  1. Pull the trigger and the primer ignites the propellant.
  2. Igniting the propellant results in an ever-increasing volume of gases.
  3. The pressure continues to rise until the powder completely burns.
  4. The shot charge exits the muzzle.

How John Browning Would Describe It
As the gas is still building pressure and the slow-burning powder still combusting, a small portion of gas is bled off through one or two ports about six inches from the mouth of the chamber.  As the wad and steel shot pass these ports, a squirt of high-pressure gas shoots through the ports and gives a hard, swift shove to the gas piston.  The piston travels rapidly to the rear until it passes the vent where the pressure drops.  The inertia imparted by the gas piston to the sleeve that surrounds the magazine tube is traveling rearward, which opens the action.  The bolt is driven to the rear which ejects the spent shell hull.  If a fresh round is in the magazine, it is brought into alignment with the bolt , which is then chambered as the bolt returns to battery.

Berettas in Particular
The vent is radiator-shaped and allows the gas to escape in front of the fore end.    Magnum loads require the gun to have additional mechanisms to vent the higher pressure gases otherwise the incessant pounding would damage the action.  There is a spring-activated plunger that is forced open to vent these gases.  Gas-operated shotguns require more frequent and intensive servicing since the carbon and unburned powder blows directly from the gas ports into the mechanism of the shotgun.

Never Never Use WD-40
This product is for penetrating locks and lug nuts and is “Water-Displacing -that’s what the WD stands for.  It penetrates, evaporates, and leaves a wax-like preservative substance which protects metal finishes.  The substance left behind also collects carbon, unburned powder, dust, dirt and crud.