SBR gas advice for suppressed ( bcg vs block)

quattroginger · Mar 27, 2017

looking for advice on the gas system for my first sbr build. i will be switching between suppressed and non suppressed. i was considering a noveske upper with switchblock but my buddy told me i should just go with a adjustable bcg. looks like Bootleg and Gemtech (made by Bootleg) make these.

Does anyone have any experience or knowledge of these? pros or cons?

outrider58 · Mar 27, 2017

quattroginger said:
looking for advice on the gas system for my first sbr build. i will be switching between suppressed and non suppressed. i was considering a noveske upper with switchblock but my buddy told me i should just go with a adjustable bcg. looks like Bootleg and Gemtech (made by Bootleg) make these.

Does anyone have any experience or knowledge of these? pros or cons?

Just put a Noveske 10.5 on one of my SBRs. Shot it for the first time yesterday. Had one hicup where one of my mags wouldn't cycle without the can on. Ran out of ammo and time to figure it out.

All my other ARs and SBRs have SLR GBs on them and work very well. I would not mess with the adjustable BCGs. You already have additional blowback into your receiver from the suppressor, why add more? My 2¢

quattroginger · Mar 27, 2017

thanks for info outrider. do you have your block set to only suppressed or is it the adjustable one?

outrider58 · Mar 27, 2017

The SLR blocks are click adjustable and easily accessible. I normally have two settings, one for suppressed and one for non.

The bleedoff type BCGs would be more difficult to tune, I would think. I have not tried one though, so I might be full of crap.

quattroginger · Mar 27, 2017

outrider58 said:
The SLR blocks are click adjustable and easily accessible. I normally have two settings, one for suppressed and one for non.

The bleedoff type BCGs would be more difficult to tune, I would think. I have not tried one though, so I might be full of crap.

ahhh got it. thanks. when you sid all your others thought you menat you were using something different on the noveske. appreciate the info.

outrider58 · Mar 27, 2017

quattroginger said:
ahhh got it. thanks. when you sid all your others thought you menat you were using something different on the noveske. appreciate the info.

The Noveske has a "Switchblock". All the others have SLR adjustable blocks.

clandestine · Mar 27, 2017

Would you want a car with just 3 speeds no matter what fuel or terrain you drive in?

That is what a Switchblock or Gemtec BCG gets you. They dont have a ide range of settings. There are too many variables in the civilian AR market such as ammunition, gas port size, gas system length, dwell time, receiver extension length & buifer weight/type, calibers, chamber/throat type and so on....

Generally, if you plan to switch between suppressed, non suopressed, and change ammo types, you want click adjustable gas (preferrably SLR) and have the gas port slightly larger than it should be to ensure the gun has enough has flow so the gas block has enough flow range to ensure it will run with all ammo types. You dont need super heavy buffers as they can make cycling with low port pressure ammo not possible. A H Carbine Buffer or a Standard Rifle Buffer is what I suggest.

Avoid Aluminum Gas Blocks and any that dont have a repeatable metering system (absence of settings/clicks). Also avoid Gas Blocks that are difficult to service, get parts for and have poor customer service. Basically this leaves SLR.

clandestine · Mar 27, 2017

Outrider knows his stuff quattroginger.

IMBLITZVT · Mar 27, 2017

outrider58 said:
All my other ARs and SBRs have SLR GBs on them and work very well. I would not mess with the adjustable BCGs. You already have additional blowback into your receiver from the suppressor, why add more? My 2¢

I have a slightly different take...

First, Gemtech Adjustable bolt carrier does not vent into the receiver. It blows out the ejections port.

That said, I have not found an adjustable bolt carrier that I like, Gemtechs is the only one that will allow for FA firing, which is what I am shooting. I really hate that I can not change the setting without taking the bolt carrier out of the gun. I currently have this on my night shooting gun. So what am I going to do... take the gun apart in the dark to change the setting on the bolt. I kind of get why they did that... but it sucks.

All other adjustable Bolt Carriers, including Bootlegs, are not set up for FA. This just seems stupid to me and means I can't use them.

The SLR. I also currently have one of these set up on my night gun. Again, what am I going to do... fumble around in the dark for an Allen Wrench... Also, Allen Wrenchs are a bit hard to store on a gun. I have tons of stocks, and uppers and constantly switch out stuff. How long before the Allen wrench gets forgotten or lost? Actually the first time I was out with it, I had adjusted it closed to start and left the Allen key at home. I had a single shot gun that day! It sucked. I know that in the heat of getting ready sometimes stuff is forgotten. Thats why I always feel like guns should work with NO TOOLS!

Second issue is that I can't remember crap... do I turn three clicks that way or this way? I would never be able to remember what I need to do...

So to me the SLR is a good product in the wrong application for my purpose.

So what do I suggest... Well I am testing these out now: http://micromoa.com/govnah-gas-blocks/

They are two or three position adjustable gas blocks that work off a plate. You move the plate to the hole size you need. I got the two position plate... one for Suppressed, one for normal. Use a bullet tip to change it. No bullet tip... no ammo to shoot anyway!

Now I did have to shave them down to fit my Aero COP upper. Also I have only tried it unsuppressed so far... but I am hoping this is the best answer.

Clandestine asks if you want only 2 positions or a range. Fair question for sure. For me, I want the extra ass in there to work no matter what and would not fine tune it. I am not punching paper and I am shooting it on FA. My goal is only to knock down the gas that blows back in my face. I am hoping it will do that. So it really does depend on what you are looking to do with the gun! For Clandestine's purposes, I am sure he is right, that the SLR is way to go for him. For me... its not what I am looking for. I should also say that you can buy these adjustable plates with different hole sizes... so its harder to fine tune and much expensive but it can be done.

Hope that helps... or at least is a different point of view...

cokebuck · Mar 27, 2017

Big time SLR adjustable user here, on mid length and rifle length systems. From zero, 4 clicks open for suppressed and another 3 clicks open for unsuppressed. Works great for casual range shooter, no nighttime, FA or life & death situations. For those situations, gas blow back might be the last thing I'm worrying about.

clandestine · Mar 27, 2017

IMBLITZVT said:
I have a slightly different take...

First, Gemtech Adjustable bolt carrier does not vent into the receiver. It blows out the ejections port.

That said, I have not found an adjustable bolt carrier that I like, Gemtechs is the only one that will allow for FA firing, which is what I am shooting. I really hate that I can not change the setting without taking the bolt carrier out of the gun. I currently have this on my night shooting gun. So what am I going to do... take the gun apart in the dark to change the setting on the bolt. I kind of get why they did that... but it sucks.

All other adjustable Bolt Carriers, including Bootlegs, are not set up for FA. This just seems stupid to me and means I can't use them.

The SLR. I also currently have one of these set up on my night gun. Again, what am I going to do... fumble around in the dark for an Allen Wrench... Also, Allen Wrenchs are a bit hard to store on a gun. I have tons of stocks, and uppers and constantly switch out stuff. How long before the Allen wrench gets forgotten or lost? Actually the first time I was out with it, I had adjusted it closed to start and left the Allen key at home. I had a single shot gun that day! It sucked. I know that in the heat of getting ready sometimes stuff is forgotten. Thats why I always feel like guns should work with NO TOOLS!

Second issue is that I can't remember crap... do I turn three clicks that way or this way? I would never be able to remember what I need to do...

So to me the SLR is a good product in the wrong application for my purpose.

So what do I suggest... Well I am testing these out now: http://micromoa.com/govnah-gas-blocks/

They are two or three position adjustable gas blocks that work off a plate. You move the plate to the hole size you need. I got the two position plate... one for Suppressed, one for normal. Use a bullet tip to change it. No bullet tip... no ammo to shoot anyway!

Now I did have to shave them down to fit my Aero COP upper. Also I have only tried it unsuppressed so far... but I am hoping this is the best answer.

Clandestine asks if you want only 2 positions or a range. Fair question for sure. For me, I want the extra ass in there to work no matter what and would not fine tune it. I am not punching paper and I am shooting it on FA. My goal is only to knock down the gas that blows back in my face. I am hoping it will do that. So it really does depend on what you are looking to do with the gun! For Clandestine's purposes, I am sure he is right, that the SLR is way to go for him. For me... its not what I am looking for. I should also say that you can buy these adjustable plates with different hole sizes... so its harder to fine tune and much expensive but it can be done.

Hope that helps... or at least is a different point of view...

My purposes are for hard use and suppressed guns.

I dont tinker with gas settings on the fly, I do that at a static range to find my gas settings, this is not much different than finding my dope for certain ammo or zeroing my Sights/Optics.

Simple solution for the tool issue.... It gets stored or attached to the gun. Just as other tools I need are stored on the gun to adjust optics, or to tighten something that may come loose.

Generally, you set the gas on the block based on the ammo you shoot, and with or without a suppressor before shooting. Just as I would with other pre-shooting checks like loading mags, checking Optic Batteries, Light Batteries, N.V./Laser/Illuminator Batteries, checking my optic glass for fouling, ensuring the BCG and FCG is lubricated, inspecting the sling, doing a safety check, and so on.

The settings are simple. Turn the adjuster in till it stops, that is setting 0, then work it out till you reach your adjustment for the ammo and muzzle device you selected.

OrbitalEllipses · Mar 27, 2017

FWIW, Gemtech carrier is produced by Bootleg. Bootleg version is adjustable without disassembly.

outrider58 · Mar 27, 2017

OrbitalEllipses said:
FWIW, Gemtech carrier is produced by Bootleg. Bootleg version is adjustable without disassembly.

Do you own/use one?

IMBLITZVT · Mar 27, 2017

clandestine said:
Simple solution for the tool issue.... It gets stored or attached to the gun. Just as other tools I need are stored on the gun to adjust optics, or to tighten something that may come loose.

Yeah, for me with a Registered lower, its a bit of a mix at all times. I have two 11.5", a 14.5", a 16" IAR, a 12",16",20" Shrike and a 9mm upper all running off one lower and I have not even ventured out into 22LR, 5.45, 7.62...etc. So for me, keeping it simple as possible is paramount. Storage is usually in the P Grip which stays with lower. Stocks, which change depending on upper. Vertical grips that get shared between uppers. So keeping batteries is hard enough, tools... if it breaks, you have another upper to shoot!

We just come at this very differently.

Generally, you set the gas on the block based on the ammo you shoot, and with or without a suppressor before shooting. Just as I would with other pre-shooting checks like loading mags, checking Optic Batteries, Light Batteries, N.V./Laser/Illuminator Batteries, checking my optic glass for fouling, ensuring the BCG and FCG is lubricated, inspecting the sling, doing a safety check, and so on.

Yeah, with MGs, you are always looking to save a bit on ammo. So I am running whatever I find and I adjust to basically shoot anything and after 1000s of rounds with no cleaning. So I don't get optimal performance out of things but I also don't go cheap. I buy quality stuff that will hold up to what I am putting it through. Its been working so far and seems to be what most MGers are doing. I don't even think I have a sling to inspect!

My check is ammo, mags, gun... go!

Its like anything else, you have to see what you purpose is and adjust accordingly. I think the SLR is the best options for an adjustable block. I just don't really want to adjust with a tool. Troy's adjustable block is nice but is so limiting... I am liking these Govnahs, so far... I hope they work out as well as I think they might.

OrbitalEllipses said:
FWIW, Gemtech carrier is produced by Bootleg. Bootleg version is adjustable without disassembly.

Yes but its a light weight carrier not Full Auto rated.

I know it might be a bit arrogant but I feel like if its not going to hold up to FA fire, its not good enough to buy... That said I think its because of the light weight in this case...

OrbitalEllipses · Mar 27, 2017

outrider58 said:
Do you own/use one?

No, I have two SLR blocks...though I'm not entirely happy with them.

IMBLITZVT said:
Yes but its a light weight carrier not Full Auto rated.

I know it might be a bit arrogant but I feel like if its not going to hold up to FA fire, its not good enough to buy... That said I think its because of the light weight in this case...

Eh, a 'Full Auto' bolt could blow to smithereens, just depends on the construction and QA. If you're not using it on FA, I wouldn't worry about it though for you perhaps FA rating is important.

.

rayrevolver · Mar 27, 2017

Another option: Get an appropriate sized gas port that supports both suppressed and unsuppressed shooting. The idea is that you use a heavier buffer suppressed.

Black River Tactical makes gas block inserts to get you into the reasonable port size for a specific setup. Non-adjustable and fool proof!

...I went with SLR even with a 100% suppressed only upper (11.5" Mid Length). It works but makes me nervous!

outrider58 · Mar 27, 2017

cokebuck said:
Big time SLR adjustable user here, on mid length and rifle length systems. From zero, 4 clicks open for suppressed and another 3 clicks open for unsuppressed. Works great for casual range shooter, no nighttime, FA or life & death situations. For those situations, gas blow back might be the last thing I'm worrying about.

That's a pretty good rule of thumb in most cases. :thumbsup:

IMBLITZVT said:
I have a slightly different take...

First, Gemtech Adjustable bolt carrier does not vent into the receiver. It blows out the ejections port.

That said, I have not found an adjustable bolt carrier that I like, Gemtechs is the only one that will allow for FA firing, which is what I am shooting. I really hate that I can not change the setting without taking the bolt carrier out of the gun. I currently have this on my night shooting gun. So what am I going to do... take the gun apart in the dark to change the setting on the bolt. I kind of get why they did that... but it sucks.

All other adjustable Bolt Carriers, including Bootlegs, are not set up for FA. This just seems stupid to me and means I can't use them.

The SLR. I also currently have one of these set up on my night gun. Again, what am I going to do... fumble around in the dark for an Allen Wrench... Also, Allen Wrenchs are a bit hard to store on a gun. I have tons of stocks, and uppers and constantly switch out stuff. How long before the Allen wrench gets forgotten or lost? Actually the first time I was out with it, I had adjusted it closed to start and left the Allen key at home. I had a single shot gun that day! It sucked. I know that in the heat of getting ready sometimes stuff is forgotten. Thats why I always feel like guns should work with NO TOOLS!

Second issue is that I can't remember crap... do I turn three clicks that way or this way? I would never be able to remember what I need to do...

So to me the SLR is a good product in the wrong application for my purpose.

So what do I suggest... Well I am testing these out now: http://micromoa.com/govnah-gas-blocks/

They are two or three position adjustable gas blocks that work off a plate. You move the plate to the hole size you need. I got the two position plate... one for Suppressed, one for normal. Use a bullet tip to change it. No bullet tip... no ammo to shoot anyway!

Now I did have to shave them down to fit my Aero COP upper. Also I have only tried it unsuppressed so far... but I am hoping this is the best answer.

Clandestine asks if you want only 2 positions or a range. Fair question for sure. For me, I want the extra ass in there to work no matter what and would not fine tune it. I am not punching paper and I am shooting it on FA. My goal is only to knock down the gas that blows back in my face. I am hoping it will do that. So it really does depend on what you are looking to do with the gun! For Clandestine's purposes, I am sure he is right, that the SLR is way to go for him. For me... its not what I am looking for. I should also say that you can buy these adjustable plates with different hole sizes... so its harder to fine tune and much expensive but it can be done.

Hope that helps... or at least is a different point of view...

Now, do you shoot your MG suppressed, or are you just trying to tame the various ammo types you are shooting? I am not an FA guy(never have had the opportunity to play with a 'giggle switch') so I'm trying to learn here. Thanks!

IMBLITZVT · Mar 27, 2017

OrbitalEllipses said:
...
Eh, a 'Full Auto' bolt could blow to smithereens, just depends on the construction and QA. If you're not using it on FA, I wouldn't worry about it though for you perhaps FA rating is important. .

Actually I have seen FA gun blow parts to smithereens! I saw one of those hydraulic buffer literally explode in a gun... its like the gun pissed itself! Other parts too but that one was cool. One thing is for sure... someone tells you it will not work in FA... you can bet its really not going to work with FA. However in this case, lightening the bolt will probably play hell with the cycle rate of the gun. On my Mac, I bought a Tungsten bolt and it dropped the rate of fire down to 1/2 of what it was with the same bolt made in steel! Granted thats an unlocked system.

outrider58 said:
....
Now, do you shoot your MG suppressed, or are you just trying to tame the various ammo types you are shooting? I am not an FA guy(never have had the opportunity to play with a 'giggle switch') so I'm trying to learn here. Thanks!

Yes, I shoot MGs suppressed. With that the volume of gas becomes the hardest issue to deal with. You are getting gassed as you shoot on many guns. Its really not that fun to shoot that way unless you have googles and don't breath. For example, on my Shrike which is a belt fed M16... I am getting a 30 caliber Omega over the 556 Saker because I need the extra volume to keep from gassing myself. Thats a piston system and even with it turned down its still not fun. No its not really about ammo selection at all.

Frankly, I find that SBRs and Suppressors are much more popular with semi auto guns. In the FA world, SBRs get annoying with the blast and extra noise and reduced ability to control the gun. Suppressor gas you out and they get smoking hot long before the barrel gets hot. You have to shot shooting like 30 mins before you are ready to leave!

That said, I still plan to have it as an option. On my night shoots its proving much more useful.

inkd · Mar 27, 2017

quattroginger said:
looking for advice on the gas system for my first sbr build. i will be switching between suppressed and non suppressed. i was considering a noveske upper with switchblock but my buddy told me i should just go with a adjustable bcg. looks like Bootleg and Gemtech (made by Bootleg) make these.

Does anyone have any experience or knowledge of these? pros or cons?

I have a Noveske Switchblock I run suppressed and a couple AR's with SLR's I also run suppressed.

I am happy with the both of them but I give a slight nod to the SLR for the ability to be able to "tune" it down a bit more precisely. My guns with the SLR adjusted correctly runs a little "softer", not like an AR recoils much anyway but I feel like I have the recoil impulse of a longer gas system in a shorter package, if that makes any sense?

I do like the ability of being able to switch back and forth with no tools on the Switchblock, but, to me, it's not a big enough of a deal for me to go all Switchblock.

If you set the gun up with an SLR on a cold day, with the suppressor, and get it to the setting where it will reliably cycle and lock back, you should be good to go in a pretty wide range of conditions.

On my latest build, I used a Noveske barrel with an SLR adjustable block.

As far as the adjustable BCG's, I've never used one so I can't comment on them but they do not interest me in the least.

quattroginger · Mar 28, 2017

lots of great info as always. thanks everyone.

SBR gas advice for suppressed ( bcg vs block)

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