Need some advise from the gassers...

trauma1

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May 23, 2012
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I have decided to play around with my AR. Plan is to get new barrel, gas block, springs/ buffer.
My question today is .... What adjustable, clamp on, .750 gas block do you guys recommend?

Are they all the same?
Thanks for you time and input.
 
They all function basically the same. Most folks seem to have strong opinions about “best”.
I have used several and all set easily and stay set. No issues. JP, SLR and several others. I do prefer clamp on to set screw models in theory.
 
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You either need to set up for suppressed or unsuppressed.
You can get a Noveski Switchblock which has 3 settings. Off, suppressed and unsuppressed. No other adjustments.
 
I’ve had 4. Never tried the superlative though. Of the 4 my fave was the Odin works tunable for like $50 in stainless. Im set it and forget it generally with them though, not dialing up the gas and down (and never suppressed).
 
The main benefit to an adjustable gas block is allowing you to tune your AR for reliability and gas control. The shorter the barrel, the more important controlling gas and dwell time become. It also makes a difference if you want to suppress your gun as increased back pressure comes into play....and an overly gassed rifle will be harder on the gun and recoil more.

I've tried a few. Noveske's switchblock is my favorite. Just stupid simple, robust, and works. It avoids overly fussing with the gas setting, no need to count/remember clicks or turns, requires no tools to change settings, and is fast. You don't even need to unload the gun to safely change settings.

SLR's are ok. They are nice when they work. However, I've broken two with 7.5 inch 5.56 guns. SLR replaced them quickly with no fuss. I'm running another on an 18 inch SPR. Jury is still out on that one. I keep the adjustment wrench in the grip of the gun(s) because without it, you are not changing settings.

My JP adjustable gas block on a 7.62 gun has been reliable. Adjustment wrench stays in the range bag with this one.

Another option I have not tried but that many rave about are adjustable BCG's from Bootleg. If I was starting over, I'd be doing my homework on those as well.
 
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I like the SLR, has a detent so its "click" adjustable. Makes it easy to move between settings if you want to. I was an idiot and broke the leaf spring holding the detent in on one of mine, emailed them asking if I could purchase a new one, they sent me one for free and I had it in like 3 days no questions asked.
 
Superlative is, far and away, the best I’ve used, and I’ve used every one mentioned thus far in the thread. Very positive detents that don’t get gummy for at least 5k rounds of steelcase. If your barrel is gassed right, you can also take advantage of venting mode for even more pleasant shooting.
 
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Here’s the truth. If the barrel has a proper sized gas port, you don’t need an adjustable gas block whether you’re shooting suppressed or not.

An adjustable gas block is just another moving part that can cause issues if/when it fails.

The buffer system controls the speed of the bolt carrier. If you’re bolt is slamming against the buffer and beating up your brass, you fix it by adding more weight to your buffer. You don’t fix it by just using a screw to modulate pressure.

If the heavy buffer doesn’t fix it, you have a barrel with an oversized gas port. In other words, the adjustable gas block is a solution for improperly sized gas ports in barrels.
 
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Here’s the truth. If the barrel has a proper sized gas port, you don’t need an adjustable gas block whether you’re shooting suppressed or not.

An adjustable gas block is just another moving part that can cause issues if/when it fails.

The buffer system controls the speed of the bolt carrier. If you’re bolt is slamming against the buffer and beating up your brass, you fix it by adding more weight to your buffer. You don’t fix it by just using a screw to modulate pressure.

If the heavy buffer doesn’t fix it, you have a barrel with an oversized gas port. In other words, the adjustable gas block is a solution for improperly sized gas ports in barrels.

Well, you got about 1/4 of that correct.
 
In other words, the adjustable gas block is a solution for improperly sized gas ports in barrels.

Your post gets some things right but there’s a little more to it than your conclusion man.

Ever tuned a rifle with a low mass (<8oz) bolt carrier and buffer where you’re trying to get it to just barely cycle by the skin of its teeth like for 3gun?

That’s FAR from the only reason for an adjustable gas block just giving an example I’m a little familiar with. All it does is introduce another adjustment point into the gas/action/buffer/spring system.
 
Your post gets some things right but there’s a little more to it than your conclusion man.

Ever tuned a rifle with a low mass (<8oz) bolt carrier and buffer where you’re trying to get it to just barely cycle by the skin of its teeth like for 3gun?

That’s FAR from the only reason for an adjustable gas block just giving an example I’m a little familiar with. All it does is introduce another adjustment point into the gas/action/buffer/spring system.

That’s more of a niche setup though. I have played around with jp low mass carriers and adjustable gas blocks. It shoots smooooooth that way I will admit. However, my 11.5” noveske with fixed gas block also cycles really smooth and I can shoot .15-.17 splits just as easily.

I’ve see a fair amount of these competition guns have malfunctions during stages. The only ones that I haven’t seen miss a beat are JP rifles built from the factory.

I have an adjustable gas block on my precision AR, but fixed on my SBR that I almost exclusively shoot suppressed. I never saw a problem with adjustable gas blocks until screws started seizing up and whenever I changed ammo types or went from suppressed to non suppressed, I always had to play with the settings.

If the port is drilled properly, you shouldn’t “need” an adjustable gas block is what I am saying.
 
That’s more of a niche setup though. I have played around with jp low mass carriers and adjustable gas blocks. It shoots smooooooth that way I will admit. However, my 11.5” noveske with fixed gas block also cycles really smooth and I can shoot .15-.17 splits just as easily.

I’ve see a fair amount of these competition guns have malfunctions during stages. The only ones that I haven’t seen miss a beat are JP rifles built from the factory.

I have an adjustable gas block on my precision AR, but fixed on my SBR that I almost exclusively shoot suppressed. I never saw a problem with adjustable gas blocks until screws started seizing up and whenever I changed ammo types or went from suppressed to non suppressed, I always had to play with the settings.

If the port is drilled properly, you shouldn’t “need” an adjustable gas block is what I am saying.

I'm a Noveske fan and own multiple factory rifles. However, they are notoriously overgassed. But they are overgassed for a reason. John wanted reliability first and foremost. Overgassing his rifles plus his modified chamber design (in his stainless barrels) all were design decisions to reenforce reliability. The fact that he also knew how to finish his barrels consistently lead to better accuracy as well. But to use his rifles as an example of "correctly gassing from the get go" is not accurate. If reliability is your ultimate concern, then perhaps they are. But they certainly do not have optimally sized gas ports.

That being said, the point you raise about adjustment screws on AGB's adding another failure point is accurate. As I stated previously, I've had two SLR AGB's fail. They both failed by losing the detents on the adjustment screw. SLR quickly replaced/sent repair kits. But the failures still happened. I won't use an SLR on a fighting gun. This is also why I like Noveske's AGB. It is simple and as bulletproof as one can get. It is also the AGB I use on my "go-to" self-defense rifle. Suppressed or un-suppressed, it has give me zero issues.






N7b2qOT.jpg
 
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I'm a Noveske fan and own multiple factory rifles. However, they are notoriously overgassed. But they are overgassed for a reason. John wanted reliability first and foremost. Overgassing his rifles plus his modified chamber design (in his stainless barrels) all were design decisions to reenforce reliability. The fact that he also knew how to finish his barrels consistently lead to better accuracy as well. But to use his rifles as an example of "correctly gassing from the get go" is not accurate. If reliability is your ultimate concern, then perhaps they are. But they certainly do not have optimally sized gas ports.

That being said, the point you raise about adjustment screws on AGB's adding another failure point is accurate. As I stated previously, I've had two SLR AGB's fail. They both failed by losing the detents on the adjustment screw. SLR quickly replaced/sent repair kits. But the failures still happened. I won't use an SLR on a fighting gun. This is also why I like Noveske's AGB. It is simple and as bulletproof as one can get. It is also the AGB I use on my "go-to" self-defense rifle. Suppressed or un-suppressed, it has give me zero issues.
N7b2qOT.jpg

I should've clarified, my SBR is a DDM4 with a Noveske barrel and noveske fixed gas block that's an 11.5" barrel. It doesn't appear to be over gassed based on my experience. Especially since DD really blows open that gas port. With my DD barrel, I couldn't shoot more than a few rounds rapid fire suppressed without eating gas for dinner. The noveske doesn't give me that problem at all and shoots a lot smoother.

I can't imagine there's a port size difference for his factory built rifles vs just selling barrels. Although, I only have a sample size of one so maybe mine is the minority.

I have also had an SLR gas block fail that I had mounted on an AR10 chambered in .260rem.
 
There’s a very wide gulf between the typical default super overgassed setup, and barely-running 3gun play rifle.

A lightweight carrier and gutted buffer benefits most, but even a standard weight carrier and buffer benefit from being tuned. A couple extra clicks of gas past mag holdback is substantially smoother than uncontrolled factory gas, and never needs to be fucked with ever again.

A heavier buffer is a blunt hammer to solve a problem that can be resolved with some finesse, to great benefit. Adding reciprocating mass doesn’t strike me as a way to improve shooting dynamics, in any case.
 
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Don't these along with the Noveske Switchblock limit your rail selection though? Basically making it so you need the rail to be shorter than where the gas block is or a wide ID?

More or less.

As in most things in life, there are going to be trade offs. The individual needs to decide where their priorities lie. If my priority is simplicity and reliability, the switchblock is high on my list. If I need more rail space, perhaps I look somewhere else.
 
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More or less.

As in most things in life, there are going to be trade offs. The individual needs to decide where their priorities lie. If my priority is simplicity and reliability, the switchblock is high on my list. If I need more rail space, perhaps I look somewhere else.
Indeed, have to give something to gain something.
 
I should've clarified, my SBR is a DDM4 with a Noveske barrel and noveske fixed gas block that's an 11.5" barrel. It doesn't appear to be over gassed based on my experience. Especially since DD really blows open that gas port. With my DD barrel, I couldn't shoot more than a few rounds rapid fire suppressed without eating gas for dinner. The noveske doesn't give me that problem at all and shoots a lot smoother.

I can't imagine there's a port size difference for his factory built rifles vs just selling barrels. Although, I only have a sample size of one so maybe mine is the minority.

I have also had an SLR gas block fail that I had mounted on an AR10 chambered in .260rem.
My entire gas system and BCG is JP with the heave silent capture spring on a 260 rem. Shots like a champ.
 
They have 2 versions. The one you speak of and one that fits under the hand guard and uses an Allen key like most.
It would be nice if someone made some sort of a push button that could be accessed through the slots in the rail. Having to worry about allen keys is annoying, particularly because often times they need to be longer than your standard off the shelf allen. I remember a company at one point made such a thing but it was a strange system that required installing plates to reduce the gas.
 
It would be nice if someone made some sort of a push button that could be accessed through the slots in the rail. Having to worry about allen keys is annoying, particularly because often times they need to be longer than your standard off the shelf allen. I remember a company at one point made such a thing but it was a strange system that required installing plates to reduce the gas.

Check out the Bootleg Adjustable Bolt Carrier Group.
 
Check out the Bootleg Adjustable Bolt Carrier Group.

I like the Bootleg on my 12.5" Grendel SBR for switching between suppressed and unsuppressed. It works great to switch like that when paired with properly adjusted gas (either a tuned gas block or correct size gas port - same effect either way). It is not a very good substitute for an adjustable gas block though, and that's not what it's made for; it doesn't have the range of adjustment you need for a good adjustable gas block.

WmecOw3.jpg
 
Superlative Arms AGB+Tubb's Flatwire Spring and the standard weight buffer of your choice.

If you really want to dump money into it the LMT Enhanced BCG (well really just the carrier) delays unlock via a modified cam pin path and more venting, further decreasing blowback. Add a GMS Tactical GMS-15 Gen II charging handle and you'll wonder if you are shooting suppressed at all. Best setup I've used for a suppressed AR for sure.

Also fair to mention you should be using the longest gas system you can on a given barrel.
 
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Ever since Geissele came out with that DIY pin on gas block, I haven't used anything else. I'm not a fan of set screws though I have a few done that way. But Geissele makes this gas block that first goes on with one set screw, then that basically holds it in place while you drill out the pre-drilled hole for the pin. It uses a fatter than normal roll pin and they ain't going anywhere once installed. Fairly low profile, I don't understand the use of anything else when these will fit.

German, I agree, KAC is the titties but you know as well as I do that nobody is DIY'ing KAC gas blocks on home builds. Though it would be nice if that method of installing gas blocks became the standard. I dread having to replace that barrel one day...