In today’s high tech semiautomatic shotguns there are basically 2 types: Gas or Inertia. You may have both types, or only one type.
Each system has its own set of strengths and weaknesses. If you don’t know which type your favorite auto loader is, we will go over those and how each works respectively.
Gas Guns- Gas shotguns bleed off a small amount of gas from the shell that is being fired. The barrel will have small ports in it to collect the portion of gas to drive the gas piston. The gas pushes a ring shaped piston that uses the magazine tube as a slide to ride on. Which in turn pushes the bolt back and ejecting the spent shell, then moving back forward without the presence of the gas and picking up a new shell.
Gas guns have pretty much been the standard and go to shotgun for the last 40-50 years.
Significantly less recoil. The recoil is spread out over a larger part of the shotgun and is less direct than an inertia driven gun.
Tried and True- Gas systems have been around for decades and are a proven weapon in the field.
Harder to keep clean. Carbon residue will build up in all of the mechanisms and cause failures and jams if not cleaned regularly.
Less Cold Weather Tolerant. When the mercury starts to dip, gas guns can have a tendency to foul more often as the lubrication, carbon and unspent powder residue will be less fluid and become more sticky.
Inertia Guns- Inertia guns operate by the breech bolt being held in in the chamber by a spring, and when a round is fired the spring will be depressed by the rearward inertia of the gun. Then it will release the bolt to move rearward, thus ejecting the spent shell and picking up a fresh shell from the magazine.
Inertia was essentially brought to the forefront of shotguns by Benelli. Now Franchi, Stoeger and other have picked up the inertia driven systems as well.
Very Clean. Inertia systems are by far the cleanest operating auto loading shotguns made.
Less Moving Parts. There are no special gas pistons or O rings or ports to clean. You will see from the pic how the inertia gun has less moving parts. Which usually equals more reliability.
More Recoil. There is nowhere for the recoil to go but through the stock and directly to the shooter’s shoulder. Inertia gun manufacturers have tried to overcome these issues with high tech recoil pads, softer combs and collapsing stocks.
Stock Trash Build Up. With inertia driven weapons anything that gets inside the gun will find its way into the stock spring mechanism. It will require frequent cleaning and can cause the spring and bolt to move much slower.
In conclusion, both Gas and Inertia driven shotguns are here to stay. Both are highly reliable and effective tools to shoot whatever game you pursue. To some it is a matter of how one feels or simple preference. Which gun you choose is completely up to you.
I just wanted to touch on a subject that I often get asked about. I don’t think there are any winners or losers when it comes to either of these systems, as both are extremely effective.