June 15, 2024
This whole shot process happens because of the laws of physics. Equal and opposite reactions! With just a few springs and very few other moving parts, Retay shotguns use the rules of inertia to eject the spent shell and continue on to get the next shot into battery. 

By: Justin Hunold

How Inertia-Driven Shotguns Work: A Beginner’s Guide

If you’re just beginning the search for a semi-automatic shotgun, you have definitely run into the terms Inertia-Driven and Gas operated. These are the two most popular operating mechanisms for semi-auto guns. Inertia-driven shotguns are an increasingly popular choice among hunters and sport shooters thanks to their reliability and simplicity. Retay USA has the most reliable Inertia system on the planet with our Inertia Plus system. 

 If you’re new to the world of inertia-driven shotguns, you might wonder how they work and what makes them different from other types of shotguns. In this article, we’ll provide a beginner’s guide to inertia-driven shotguns and explore their incredible features and benefits.

Inertia-driven shotgun mechanism

At its core, an inertia-driven shotgun operates by using the energy from a fired shell to cycle the action of the firearm. This contrasts with gas-operated shotguns, which use gas pressure from the fired shot to cycle the action. The inertia-driven mechanism consists of a bolt carrier and a spring that compresses when the shotgun is fired, causing the bolt carrier to move rearward and cycle the action.

This whole shot process happens because of the laws of physics. Equal and opposite reactions! With just a few springs and very few other moving parts, Retay shotguns use the rules of inertia to eject the spent shell and continue on to get the next shot into battery. 

How does an inertia-driven shotgun work?

When a shotgun is fired, the energy from the fired shell is transferred to the bolt face on the bolt carrier, which then moves backward, compressing a spring inside the bolt assembly. When this spring compresses to the point of expansion, it expands out, forcing the majority of the bolt backward, this then rotates the bolt face out of battery and the entire bolt slides back. This action ejects the spent shell and positions a new shell from the magazine into the chamber. As the bolt moves back, it uses a long arm that is on the back of it to compress a recoil spring in the stock, which then sends the bolt forward as it expands. As the bolt carrier moves forward, the spring expands, pushing the carrier back into its original position, ready to fire the next shot.

Inertia-driven shotgun operation explained

Inertia-driven shotguns are designed to be simple and reliable. With no gas system to worry about, these shotguns are less prone to fouling and require less maintenance than gas-operated shotguns. Additionally, the inertia-driven mechanism allows for faster cycling and reduces felt recoil, making them easier to shoot accurately.

The physics behind inertia-driven shotguns

The key to the inertia-driven mechanism is the transfer of energy from the fired shell to the bolt carrier. This is achieved through Newton’s third law of motion, which states that for every action, there is an equal and opposite reaction. When a shotgun is fired, the energy from the expanding gases in the shell creates a force that is transferred to the bolt carrier, causing it to move rearward.

Understanding inertia in shotguns

Inertia is a measure of an object’s resistance to changes in motion. Inertia-driven shotguns use this principle to their advantage, as the bolt carrier’s mass and momentum allow it to cycle the firearm’s action. This means that the heavier the bolt carrier, the more energy it will absorb and the more reliably it will cycle the action.

Inertia-driven vs. Gas-operated shotguns

While inertia-driven shotguns have many advantages, gas-operated shotguns are still popular among hunters and sports shooters. Gas-operated shotguns use gas pressure from the fired shell to cycle the action, which can result in reduced recoil and faster cycling. However, gas-operated shotguns are also more prone to fouling and require more maintenance.

Inertia-driven shotgun maintenance tips

While inertia-driven shotguns require less maintenance than gas-operated shotguns, they still need proper care and cleaning to ensure their reliability and longevity. This includes regular cleaning of the barrel, action, and magazine, as well as lubrication of moving parts. It’s also essential to use the correct ammunition for your shotgun, as using the wrong type of shell can cause malfunctions or damage to the firearm.

Final Shot

At the end of the day Retay’s Inertia Plus system is the best inertia-operated system on the planet. With no clicking, no way for the action to come out of battery, and the ability to load without “sending the bolt home,” we have taken the most reliable operating system for shotguns and made it even better. We hope this answers some of your questions about the hows and whys of inertia-driven shotguns, and we hope you check ours out!