Semi-Auto and Auto Loading Shotguns with Colonel Smoothbore
By Kelsey

Posted: October 21, 2012

This week we’ll take a look at semi-auto or auto loading shotguns. The idea behind these guns is that with each pull of the trigger the gun fires, ejects the empty hull, and then reloads a new shell, readying the gun for a follow-up shot. This process can continue until the gun’s magazine is emptied. “Automatics” make the shooter’s job quite easy. Simply find the target, mount the gun, point, and shoot; no levers, bolts, or slides to manipulate. The only other shotgun that can provide a second shot as quickly as a semi-auto is a doublebarreled gun.

Most auto loading shotguns operate with one of three systems: gas piston, recoil, and rotating bolt. The rotating bolt guns are personified by the Benelli “Inertia Driven” and Browning “Kinematic Drive” systems. We’ll discuss these guns later.

John Browning’s recoil operated Auto 5 was the standard for all semi-auto shotguns in the 20th century. The gun was originally manufactured in Belgium by FN and marketed as the Browning Auto 5, and in the United States both Remington and Savage built and marketed the gun. Over the last 50 years I’ve taken more game birds with my Browning “Sweet Sixteen” Auto 5 than with all my other shotguns combined. But alas, like many of the great guns of the 1900’s, the manufacturing cost of the somewhat complicated design was its demise.

When fired, the recoil operated gun cycles in the following order. First the barrel and bolt, which are locked together, begin to recoil rearward. At the end of the rearward motion the bolt releases from the barrel, then the barrel is thrust forward by the compressed recoil spring that surrounds the magazine tube. The empty cartridge is ejected and the carrier lifts a fresh cartridge up from the magazine. The now recocked bolt pushes the new shell into the chamber and locks back into the barrel. The gun is once again ready to fire. All of this takes place in just a fraction of a second. Recoil operated guns are quite clean, only the interior of the barrel is exposed to burning powder. The guns can be a bit finicky about ammunition; changes between light and heavy loads often require a reconfiguration of the recoil spring, but overall they are extremely reliable.

Next week, we’ll check into the gas piston driven guns. Until then, be safe and good shooting.

Colonel Smoothbore