M*CARBO Brotherhood

MAC - AR Video That Finally Addresses My Confusion

K … so … I’ve always had a disconnect trying to understand how gas guns (specifically ARs) actually run. I’ve never made it through the explanation without asking questions that don’t get answered to my satisfaction - until tonight.

This video is worth a watch if your AR has seemingly been powered by magic all these years.

Was I the only one confused about this issue?


Well, I was skeptical but I did learn about the expansion chamber inside the bolt carrier, I wasn’t aware of the dual function of the gas impingement


@Dred I “think” the problem arose from back at the time the AR was introduced by Stoner. Big Army did not want the weapon to succeed the venerable M1 Garand, they wanted the M-14. To them it was a tinker toy and many look at the AR that way today. So some Army brass looked at the BCG and gas tube then said “Oh, yeah, gas comes out the tube and hits this little bucket here and that what’s operates the BCG”. My history may be a little fuzzy here, but the AR did not pass the trials, it took General Curtis LeMay of the Air Force to give the AR its’ beginning of legitimacy. So, I believe that, from a jaundice point of view the myth of “direct gas impingement” was born. Thanks for finding the video, very informative. :+1:


Great video good info.


That’s a big reason I went with gas piston driven. Also runs much cooler and cleaner. Typically a little more weight, but we’re not talking M-1 Garand weight here.


Sorta specifies what we call piston as a closed system piston veraus the DI ARs are actually open system piston.

At any rate, it feels good to understand the system since my first 2 landed in 2018. He also dropped a key to my understanding of how to effectively lube’m.

It was disconcerting repeatedly making inquiries of folks I thought woul know only to discover their best answer was: it just works for me.

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first ARMALITE I owned, i swore was powered by evil spirits, and magic. turned out (it was a early one) someone had decided to modify the gas tube trying to modify cycle. I can tell you from what i found, pinching it in the middle with vise grips, dont work LOLOLOL changed the tube, and everything cycled fine… I exorcised the “evil spirits”:smiling_imp::smiling_imp::smiling_imp::smiling_imp::smiling_imp: