Mid Length Gas System Guide

The mid-length gas system, often associated with firearms like the AR-15, is surrounded by misconceptions. Contrary to popular belief, it is distinct from the carbine-length system, isn't exclusive to specific barrel lengths, and offers a smoother recoil.

While not a recent innovation, its popularity has surged due to its balance in reliability and reduced wear on components. Its performance can vary based on ammunition type, and it can influence factors like recoil and barrel harmonics, affecting accuracy. 

Remember, while misconceptions exist, it's essential to research and understand the specifics of any firearm system or component before making decisions. This is your mid length gas system guide.

Mid Length Gas System Pressure Comparison

mid length gas system

Improved Reliability 

The longer dwell time in mid-length and rifle length systems means a slight delay in the bolt carrier's movement, making the feeding of new rounds into battery slightly slower but more reliable.

ar15 gas length

Longer Than Carbine Gas Length 

While both are shorter than the rifle-length system, the mid-length is longer than the carbine-length. The mid-length system positions the gas port further down the barrel, typically around 9 inches from the breech, as opposed to the carbine's 7 inches.

Mid Length Gas System Can Be Used With Various Barrel Lengths

While the mid-length system is often paired with barrels around 16 inches, it can be used with other lengths as well. The key is matching the gas system to the intended purpose and ammunition.

This extra length in the mid-length system allows for a more gradual and gentler delivery of gas to the action. The extended dwell time (the time between the bullet passing the gas port and exiting the barrel) contributes to reduced felt recoil and less wear and tear on internal components.

Slight Recoil Difference

Some shooters believe there's no noticeable difference in recoil between the various gas systems. However, the mid-length system typically offers smoother recoil compared to the carbine system, due to its longer distance from the breech. However, the buffer system and muzzle device can have additional effects.

Shorter gas systems tend to send a higher volume of gas back towards the shooter, making follow-up shots more challenging during rapid firing.

Various Ammo Performance

The performance of the mid-length system, like other gas systems, can vary based on the type of ammunition used. Some rounds might function more reliably than others.

Impact On Accuracy

The gas system length doesn't inherently dictate the accuracy of the rifle, but it can influence factors like recoil and barrel harmonics, which in turn can affect accuracy. Above all, it's up to the shooter.

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