The Fallacy of the Ideal Gas Port

The Fallacy of the Ideal Gas Port


With the advancement and mainstreaming of the short-barreled AR-style carbine and the proliferation of silencers, much work has been done to overcome the negative effects that come with short barrels and suppressors. With short barrels come short gas systems. With shortened gas systems come higher port pressures and diminished dwell time. With suppressors come an increase in the duration of system pressurization, both through the gas tube and through the bore (manifested as what's often called “back pressure”) as the escape of pressurized gasses is purposefully slowed to reduce the sound signature of each shot. All of this results in accelerated unlocking, violent extraction, increased recoil, and a number of other negative effects.


In an attempt to mitigate these detrimental factors, industry has gone to significant effort to refine, tune, or optimize gas port sizes for acceptable performance under common or selected conditions and configurations. You'll see this in the form of barrels, gas ports, or gas blocks advertised as having "reduced" or otherwise tuned port sizes. The idea is that the gas port can be sized to deliver reliability under one set of nominal conditions and probably work under most other common conditions, assuming the use of ammunition that delivers a consistent level of pressure, that a suppressor is consistently in use or not in use at all, and that environmental conditions reach neither extreme of hot or cold. This method, combined with the selection of heavier or lighter buffers and varied spring rates may indeed result in acceptable reliability in most conditions.

What simply can’t happen with a single gas port size, however, is the achievement of ideal performance under all conditions, with all ammunition, with or withouta suppressor, at the least amount of recoil and aiming disruption. There is no such thing as one ideal gas port size. As we’ve detailed in other parts of this blog, the AR requires a balanced system to perform with maximum reliability and minimum recoil for the longest possible service life. When one leg of the triangle of factors that determine AR performance (Pressure, Time, and Mass) is increased or decreased, one or both of the other two must also change for ideal performance to be reestablished (if it can be established or reestablished at all with the components in use). Any one gas port size, regardless of how ideal it is with a given type of ammo, suppressor, or set of conditions, will always be and can only be a compromise. Change ammo? Be prepared to change your buffer and/or buffer spring. Set up your carbine during the hot summer months? When winter comes you should be prepared to change your configuration again.

.223 Remington Duty Ammo

The recognition of this simple fact provided the genesis of adjustable gas systems long ago. Perhaps the most famous and ubiquitous, though obsolescent, adjustable gas system of the relatively modern era is that of the Fusil Automatique Leger or FAL rifle, but medium machineguns like the M240B also have gas systems that are adjustable by the arrangement of a multi-ported gas regulator plug. More correctly, the M240 Gas Regulator Plug allows the selection of different port sizes upon disassembly and reassembly. This isn't truly "adjustable" as disassembly of the gun and its barrel assembly is required to make changes, but is indeed a recognition that no one gas port size can possibly be ideal for all situations and configurations. We've seen the concept of adjustable gas "blocks" on AR-pattern rifles for many years. Unfortunately, the design philosophy behind all of these originated within the same set of constraints and is restricted by the same form factor. RIFLESPEED Gas Controls toss this design philosophy and its inherent limitations in the burn pit and offer truly unique and revolutionary capabilities.

RIFLESPEED Gas Controls were conceived, designed, developed, tested, validated, and manufactured to be truly military grade or duty grade solutions to the need for tool-free control of the gas system of the M4, M16, AR15, and AR10 family of rifles and carbines. Gas port sizes can now be deliberately increased to provide enough gas for the worst possible conditions with none of the negative effects of overgassing that would result without the ability to dial down the gas to the appropriate level for your current conditions. With the installation of a RIFLESPEED Gas Control to your rifle, compromise is no longer required. Need more gas? Turn it up. Need less gas? Turn it down. Extremely heavy buffer weights are no longer needed to delay the unlocking process so you can enjoy the reduced recoil and reduced aiming disruption of a lighter reciprocating assembly. This means your sights stay on target allowing for faster followup. Once you experience the incredible improvement in shootability, reliability, speed, and accuracy offered by a RIFLESPEED Gas Control you'll never want to shoot an unregulated gun again. Get yours HERE and achieve ideal performance for your carbine!

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