Adjustable Gas Block for Build

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arwoodie
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Adjustable Gas Block for Build

Post by arwoodie »

Starting my first 300 Blackout build and I'm putting together a 7" pistol. Unlike many builds, I'm only looking to shoot supersonic ammo and basically need it to work with Barnes 110 gr ammo above anything else. Is getting an adjustable gas block worth it or just keep it simple with a standard block?
exexex
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Re: Adjustable Gas Block for Build

Post by exexex »

It's nice to have options, especially if you decide to use subsonic or a suppressor. But you are a builder, so changing out a non-adjustable gas block if you decide to do it does not seem to be a huge obstacle.

Others on here (like dellet) can give you lots of real world experience. I just dabble and do a lot of reading.
20X11
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Re: Adjustable Gas Block for Build

Post by 20X11 »

It really depends on the other components of your build. Full Auto carrier and h2/h3 buffer, you probably don't need adjustable block. The other factor is the barrel port diameter. Since that is where gas originates, tuning the build to that is what you are after.
TRshootem
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Re: Adjustable Gas Block for Build

Post by TRshootem »

I have my 10.5" adjusted so supers are a bit less snappy and heavy subs run very well. The bleed off style by Superlative is my favorite so far.
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dellet
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Re: Adjustable Gas Block for Build

Post by dellet »

I would use one or take the money that a good adjustable costs and Order a barrel with a small port to begin with.

Pistol gas length barrels are so hopelessly over gassed for supers that to me they are no fun to shoot. If you’re not going to use a suppressor, the light weight makes follow up shots interesting. But it’s all subjective, based on a feeling. You won’t know if it benefits you until you try.
300 Blackout, not just for sub-sonics.
cdl
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Re: Adjustable Gas Block for Build

Post by cdl »

+1 on the bleed-off Superlative. (No the bleed doesn't make it louder. It's not a f'n giant hole like when an AK pops).

A nice build will have one. Give you bragging rights. Let you experiment.

That said...I leave mine setup for subs, right there at 5 turns or neutral. Seems I either forget to set it, re-set it or know where it's set if I don't leave it there. Supers are harsher than need be, but I generally don't notice it till I'm done and remember they didn't need to be. Old age is hard on the eyes and the mind.
EDL
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Re: Adjustable Gas Block for Build

Post by EDL »

First question "is this a fun gun or do you intend to trust your life with it?"

If it's a range toy, then have at it, add all the aftermarket adjustable twisty knob stuff you want, but if you want it as a serious defense arm, simple is much better (less things to fail or need adjusting in the middle of a fight). I'd also say that if it's for serious use, then build it as either a super shooter or a sub shooter, but not both.

The 300 is a great cartridge because of its versatility, but that versatility plays havoc with the AR. Asking a fixed gas system to handle the broad range of parameters across all the bullet weights and powder charges (and suppressed and unsuppressed) is asking a lot of it. It's kinda like putting a single gear in a car and then expecting it to go fast and be able to pull heavy trailer loads as well. You might get it to work, but it won't be particularly great at either one.

AGB's can erode changing pressures and get gunked up to the point you can't adjust them anymore. If it's for fun, then not a big deal, just something you need to deal with when it happens. AGB's are cheap enough.

If you're building the range toy and you need to control gas, I would go for the AGB before the adjustable carrier (I assume we're talking a direct impingement gun here). Limiting gas at the block means less gunk blowing into the receiver, which is always a good thing. I didn't think about it when I built my 300 Blk pistol (which will be a dedicated suppressed subsonic shooter), but I should have gotten a side charging upper for the build. Would eliminate the gas to the face from around the standard top charging handle location.
Thetodor
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Re: Adjustable Gas Block for Build

Post by Thetodor »

TRshootem wrote: Wed Aug 25, 2021 11:54 pm I have my 10.5" adjusted so supers are a bit less snappy and heavy subs run very well. The bleed off style by Superlative is my favorite so far.

Won’t the bleed off style change with use? I imagine soot deposition and sealing? I don’t think you can beat the reliability that comes with changing the actual diameter of the hole? I just got an slr sentry 7 adjustable block myself
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