It happens in milliseconds.
In fact, it happens faster than you might blink.
A port or small hole in the barrel vents gas through the gas block and into a gas tube.
The exploded diagram of the Springfield Armory SAINT Victor shows the entire gas system including the port, block and mid-length gas tube.
This is the basic operation of the direct gas impingement system (DGIS) on standard AR-15 platforms.
So, why does the length of the gas system matter?
Simply speaking, the length of the gas system is measured from the receiver to the gas port.
With handguards removed, you can see the gas tubes that transport hot gases from the front of the barrel to the bolt carrier group.
Original military M16 rifles were equipped with 20 barrels.
These rifles use a rifle-length gas system the longest found on production AR-style firearms.
The length of the gas tube or system is directly related to the length of the barrel.
The gas tube runs from the gas block and enters the top of the upper receiver. For optimal operation, the gas tube should be kept clean and unobstructed.
Dwell On This
The reason gas tube lengths and barrels matter is due to dwell time.
Heres where the balance between gas system length and barrel length comes into play.
The CAR-15 was a shortened M16 with a 10 barrel.
A port or small hole in the barrel vents gas through the gas block and into a gas tube. Shown is a low-profile gas block allowing a handguard to slide over it easily.
Initially, many manufacturers used carbine-length gas systems, and in all fairness, those rifles worked.
Nevertheless, it was not always a perfect solution.
The mid-length system offered several benefits.
The gas key on the BCG mates with the gas tube, and this is where the directed gas from the tube pushes back the BCG. Be sure tokeep your bolt carrier group clean.
Carbine-length gas system guns have relatively snappy recoil compared to rifle-length and mid-length system equipped guns.
Mid-length gas systems make the 16 barreled rifle function more reliably.
Much ink has been spilled about the perceived reliability of the platform.
Here are two mid-length gas systems used on 16″ and 18″ barrels. Mid-length gas systems provide optimum performance with barrels 14″ to 20″ in length.
The secret sauce for optimal operation is the relationship between the gas system length and barrel length.
a mid-length system will work better with an 18 barrel than a carbine-length system.
A Great Combination
Thats the reason why Springfield Armory features mid-length gas systems.
Better performance, less wear and tear on parts, less felt recoil, and good accuracy.
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