The AR-15 is a gas-operated firearm, which means that it uses the expanding gases from the fired cartridge to cycle the action.
There are three main types of gas systems found on AR-15s: carbine, rifle, and midlength.
Carbine Gas System
The carbine gas system is the shortest of the three, and it is typically found on AR-15s with barrel lengths of 14.5 inches or less. The gas port is located about 7 inches from the muzzle, and the gas tube is about 9 inches long.
Carbine gas systems are known for their light recoil and compact size. However, they can also be more prone to malfunctions than longer gas systems, especially when used with suppressed or high-powered ammunition.
Rifle Gas System
The rifle gas system is the longest of the three, and it is typically found on AR-15s with barrel lengths of 20 inches or more. The gas port is located about 12 inches from the muzzle, and the gas tube is about 16 inches long.
Rifle gas systems are known for their reliability and smooth operation. They are also less prone to malfunctions than carbine gas systems, especially when used with suppressed or high-powered ammunition. However, they are also larger and heavier than carbine gas systems.
Midlength Gas System
The midlength gas system is a compromise between the carbine and rifle gas systems. It is typically found on AR-15s with barrel lengths of 16 inches. The gas port is located about 9 inches from the muzzle, and the gas tube is about 12 inches long.
Midlength gas systems offer the best of both worlds, combining the light recoil and compact size of a carbine gas system with the reliability and smooth operation of a rifle gas system. They are a good choice for a variety of applications, including home defense, competition shooting, and hunting.
Which Gas System is Right for You?
The best gas system for you will depend on your individual needs and preferences. If you are looking for a lightweight and compact AR-15, then the carbine gas system is a good option. If you are looking for a reliable and smooth-operating AR-15, then the rifle gas system is a better choice. And if you are looking for a gas system that offers the best of both worlds, then the midlength gas system is the way to go.
| Gas System | Gas Port Location | Gas Tube Length | Recoil |
|---|---|---|---|
| Carbine | 7″ from Muzzle | 9 Inches | Light |
| Rifle | 12″ from Muzzle | 16 Inches | Heavy |
| Midlength | 9″ from Muzzle | 12 Inches | Medium |
Conclusion
The AR-15 is a versatile and reliable firearm, and the choice of gas system is an important one that can affect the performance and reliability of the rifle. By understanding the differences between the three main types of gas systems, you can choose the one that is best suited for your needs.
