The future looks bright for the semi-auto shotgun, a favourite among waterfowlers and pigeon and crow hunters. Gas-operated and recoil-operated versions both have their devotees. Browning has two of the most competitive models on the market in the gas-operated Maxus and the inertia-operated A5. Here is a quick look at how these two systems work, and their strengths and weaknesses.
Gas-operated reloading technology comes straight from the battlefield. The legendary M1 Garand semi-automatic rifle issued to American GIs was one of the first guns to use some of the gas from the fired cartridge to push the bolt backwards and reload the next round. A semi-auto shotgun works in exactly the same way, with one notable difference in that the gas port is much closer to the bolt. This is due to the lower pressures involved, with a 12-gauge cartridge generating less gas than a 300WM or 30-06Spr, which therefore requires a shorter route to travel.
A relatively straightforward system
The barrel or the chamber is ported at certain points to harness some of the gas from the first shot. This gas impinges on a ring-shaped piston, which is guided along the magazine tube. The bolt is thrown back and the shell ejected. When the bolt moves back into position, the next shell is chambered. Simple, really.
There are two reasons for the pleasant shooting experience you get from the Maxus: the gas-operated system and the engineering genius of the Browning gunsmiths who developed the unique Power Drive gas system. As some of the gas is taken off for reloading, some of the recoil is drawn in by the moving parts. The usually heavier weight of these shotguns lessens the recoil further, thanks to the aforementioned moving parts. Another plus point, is that gas-operated semi-auto shotguns can fire a wide range of cartridges, usually starting with 28 or 32g loads. On the downside, it should be noted that these guns need very careful cleaning. Carbon, powder and oil residues can hinder cycling and lead to jamming.
A fantastic invention from John Moses Browning!
Whether you’re firing an inertia shotgun made by Browning or a competitor, you’re still firing a Browning! In 1903, John Moses Browning invented the Auto-5, the forerunner of the A5 and the first inertia-operated shotgun.
A story about springs
The bolt is held closed by a spring. On firing, the spring is compressed by the recoil, opening the ejection port. You know the rest: the spring extends back out, taking the bolt and the next shell with it. The mechanics behind the principle can vary in a number of ways depending on the manufacturer and the era. But the idea is still the same!
Like other inertia-operated semi-auto shotguns, one major strength of the A5 is its unshakeable reliability. There are two reasons for this. The first is the almost total lack of moving parts. There are no pistons or gas ports to clean on the A5. Inertia shotguns are generally lighter than their gas-operated counterparts for this reason. However, there are two sides to every story! Inertia shotguns typically have greater recoil than their gas-operated cousins. How so? Because the recoil has nowhere to go, except towards the stock and your shoulder. But don’t forget that with the A5 you get the superbly efficient Inflex II recoil pad. Another drawback compared to the gas operation system is the choice of shell. Since the spring force cannot be adjusted (unlike the gas pressure), inertia shotguns are generally more particular about which shells can be used.
So, now that you have all the facts, which side are you on: A5 or Maxus? Tell us about your experiences!