Importance of Adjustable Gas?

[Difranco]

I am working on my 2nd AR build and my first Grendel build. I purchased my barrel from AR Buildbox from this forum.

During the transaction he asked if I was installing adjustable gas, I was thinking about it (at the block) and he recommended the Rubber City gas key or bolt carrier w/gas key.

I already have a bolt carrier that was dog eared for the project, but didn't want to change out the gas key because I didn't want to go through the process of staking the new key in place.

So how critical is being able to adjust the gas? I'd think wide open the rifle should cycle fine. And with a rifle length buffer/tube/spring that it shouldn't be overly gassed?

What am I missing?

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[LRRPF52]

The only reason I suggested considering adjustable gas with that barrel is because the port is .094" on an 18" MLGS, which is much larger than ideal.

I would look at the JP Silent Captured Spring system and see if that tames your gas system set-up. They are sprung and buffered heavily.

[Difranco]

Well I haven't even shot the thing yet. I'm going to go pickup a couple boxes of factory Hornady cartridges today. So I don't know if it needs to be tamed or not. Just wondering what other's experiences are, as I'm itching to go shoot it. The JP Silent Captured system is on my to do list.

Once I confirm no problems with the rifle, I'll go back an locktite the gas block and start adding the do dads.

And thanks for the tip on the Luth-AR stock. That was definitely the right choice.

[cst]

I have the silent capture spring on my lilja build.....I really can't tell any difference with or without it.....but I have a surefire brake and adjustable SLR gas block....and the grendel doesn't recoil that hard to begin with.......BUT...after using an adjustable block.....I can't go back to a standard one. All my guns have em now.the brake with the gas block made the most difference.

The jb captured spring g comes alittle too light out of the box and I have to turn the adjustment in more on the block...i would have to get the different spring options to make itwork on my setup if I didn't have the adjustable block. I'm not totally convinced the captured spring makes that much of a difference to warrant the price

Granted mine is a mid gas...u may not need an adjustable gas block on a rifle length..just have a H2 or h3 buffer handy when u test fire.

Besides some recoil benefit.the adjustable block allows more control over th gas when shooting with a suppressor, easier on the brass,better compenant longevity

[cory]

If LRRPF52 suggests an adjustable gas option, I'd head his advice. He's not one to suggest that just to suggest it and knows his ARs. That on top of that large of a gas port, you'll eventually resort to an adjustable gas system and wonder why you didn't do it from the beginning.

The type of adjustable gas system is where we'll disagree. While the adjustable gas key is a cool option, I prefer the staked m16 carrier due to the violent operation of the bcg. I suspect under harsh use, we'll see problems with that system. Just my speculation though.

The adjustable gas block is tried and true and more convenient to adjust.

[dmsims21]

I think I may have a similar barrel. I have a Lilja 18" with a MLGS.
I didn't start out with adjustable gas block. It worked fairly well. However, I had a feeding issue every now then, and it wouldn't always lock back on an empty magazine. I figured that I was mildly over gassed.
I switched to an adjustable gas block and all the issues went away. The action seems to stay a little cleaner too. It is easier on the dollar bills (A.K.A. Lapa brass) exiting the ejection port.

[LRRPF52]

I think the jury is still out on the adjustable gas key systems too. They choke the system in a different way than the gas block location does, so I need to play with mine and see what happens.

[NugginFutz]

I've been running my adjustable gas key every outing at the range, and the round count is about 350. At 500, I plan to take a snap of what started as a new bolt and check the wear, and again at 1,000. I'd be more than happy to accept ammo donations to get the round count up quicker!