What the big deal with Adjustable Gas blocks?

[Eagle1899]

A good example is my "Recce" style competition rifle. 18" mid weight barrel, rifle length gas system, lightweight carrier, solid delrin carbine buffer, rifle length recoil system with carbine spring and a travel reducer(also of delrin, with a through hole), muzzle brake and a Superlative Arms gas bleed adjustable gas block. I run 77 Tipped Match Kings with a healthy dose of Varget. It ejects cleanly, locks back when empty, runs dirty and has the least amount of recoil of any AR I've set up or shot that is of equal weight.

 

[Eagle1899]

On the flip side... I have a 308 Large Format AR that has a two position gas block. Un-suppressed or suppressed. I changed from a rifle length recoil system to a carbine length recoil system. I had a custom heavy weight stainless steel buffer with tungsten weights made to offset the shorter spring and less mass of the shorter buffer. It now works great and doesn't destroy brass or bolt stops.

 

[ronsatspokane]

Yeah, over gassing is the problem, a variable gas block is the solution. On a direct impingement AR the BCG is forced to cycle by gas peeled off the barrel and routed down the gas tube to the BCG. After the BCG is driven to the rear the cavity is then filled with gas. That's why the lowers get so filthy. And when seriously over gassed, as is the case when suppressed, you end up with a face full of gas. Aside from over gassing being hard on parts and brass and adding filth, the real question is how much gas to you want to eat?

 

[Wolfdog91]

Ok well thanks for all the info eveyone! I've been playing with it more and more and I honestly can say I do see the benefit of it no wrecking my brass as much and it does seem cleaner ! Not sure if it's enough to put one of these on Every build because while doing load testing today ....egghh felt like I was chasing my tail a bit

 

[SKWERLZ]

I run them when needed, they can really help getting a smooth running rifle.
If you’re already well gassed they are obviously not needed.

 

[bobcat93]

I like them, and have had a need for 2
One was for a 20 practical i put together with an 18" barrel and min length gas system..
I had to enlarge the gas port, and wanted the ability to tune as i work on load development.
That gun was deafening insanely loud, when folks talk about a laser beam for a rifle..that one was it. Absolutely incredible i was proud of myself, then i sold it.
Next was a long rang AR set up again its just another level of adjustment.
You can bleed off the excess gas to the point your rifle can run more soft. Your not beating the hell out of the recoil system, and you stay on target that much better.
Oh your being a crabby old man...hahaha
Think of home Stereo systems the more lights dials look cool...they look..well..tacti-cool..hahaha thats the only reason ya need.
Its also part of what makes AR,s so fun..you can consistently upgrade, and change things out to experiment...its that (there are many like it, but this one is mine) thing,

 

[bobcat93]

I also drilled/threaded the standard GB I used for a 17Rem upper. Not because of brass damage, but brass loss. Shooting prairie dogs, I didn't need it to eject and lose brass(no catcher at the time). Since I have played with the adjustment, with gas reduced the brass is cleaner after firing. And now have several brass catchers.

Hey how has your barrel held up with the 17rem.
Who made it? That is one amazing cartridge i had a CZ 527 in 17rem i fell in love with..sassy little thing..