The pros and cons of gas vs. inertia auto-loading shotguns
With an inertia- or recoil-operated shotgun, the breech bolt is held in in the chamber by a spring. When a round is fired, the spring is depressed by the rearward recoil of the gun. This causes the bolt to move back, ejecting the spent shell. A new shell from the magazine is then picked up on the spring’s return. Today’s popular inertia-driven shotguns include Benelli’s SBE, Franchi’s Affinity, Browning’s A5, Weatherby’s Elements and Stoeger’s M3500 series (pictured below).
The major advantages to inertia guns is that they run cleaner than gas guns and they’re mechanically simpler by virtue of having fewer moving parts (there are no gas pistons or O-rings). Simply, fewer parts can lead to increased reliability.
On the other hand, inertia guns can have problems cycling light loads. Further, they generate considerably more felt recoil, which is especially noticeable when you’re shooting high-volume magnum waterfowl loads.
Because inertia guns don’t have to conceal O-rings or a gas piston, they tend to be lighter and slimmer than gas guns. The weight also tends to be more evenly distributed on inertia guns than on gas-operated guns, which are often a little front-heavy. As a result, some hunters find inertia guns to be sportier and quicker to respond, which they like. Others, meanwhile, find the weight-forward nature of gas guns helps them achieve a much steadier follow-through, resulting in improved accuracy.
THE BOTTOM LINE
The beauty of the argument about inertia versus gas is that there is no defined winner or loser. Really, it’s a matter of preference. Just remember, though, that you’ll always shoot better with a shotgun that fits you well and feels good in your hands. Manufacturers have addressed many of the disadvantages—real and perceived—of both operating systems over the years and, as a result, both will give you years of reliable service.