When running suppressed, and let's rule out low back pressure cans because i have a reflex can in jail right now, is it more advantageous to run an adjustable gas block like a superlative arm or whatever, or use a barrel with a smaller gas port and use the appropriate buffer weight?
-
Having trouble using the site?
Contact support
adjustable gas block vs suppressor optimized gas port
- Thread starter PRSDietitian
- Start date
honest answer is it really depends heavily on the caliber, parts used in the build, and goal of the build.
example if you were making a lights-out shooting match AR in 6mm ARC, I'd go adjustable simply because it gives you more room to tune. the same could be said for a lightweight 5.56 carbine build using a lightweight BCG and buffer to reduce overall weight.
fixed gas ports are more reliable, and more economical, so those are the cases where you will often find them used these days.
As said, it depends. Are you going to be shooting loads that have bullet weights and powder burn rates on opposite ends of the spectrum? Do you want the smoothest, softest shooting setup you can have at all times? Lightweight bcg, buffer and spring? If so you probably want an adjustable.
I started to appreciate simplicity and run “normal” buffers and springs, and fixed gas blocks with brt tubes if it feels over gassed. I’ll intentionally order a brt tube with a smaller port than I probably need and will drill out until I get to where I want it to be.
Some setups are just going to be better with adjustable though. I have a 18” proof 6 arc that I can’t find a happy place where I can take the can on or off. With a fixed gas block I need an a5h0 buffer to lock back 100% but with a 762sd mounted I need to run an a5h2 or I get a lot more fouling in the receiver, mag and have sporadic ftf and stovepipe issues.
I started to appreciate simplicity and run “normal” buffers and springs, and fixed gas blocks with brt tubes if it feels over gassed. I’ll intentionally order a brt tube with a smaller port than I probably need and will drill out until I get to where I want it to be.
Some setups are just going to be better with adjustable though. I have a 18” proof 6 arc that I can’t find a happy place where I can take the can on or off. With a fixed gas block I need an a5h0 buffer to lock back 100% but with a 762sd mounted I need to run an a5h2 or I get a lot more fouling in the receiver, mag and have sporadic ftf and stovepipe issues.
So this will be a more do it all rifle. It'd be either a centurion arms enhanced socom profile barrel which has a 0.075" gas port or a Sgt of Arms/Forward Control Designs 14.5" which has a 0.0635" gas port for the suppressed version of the barrel. Plan is to use an AEM3(allen engineering is releasing an updated model in the near future)
All this said. If my can is still in purgatory, can you still reliably run a rifle with an undersized/suppressor ready gas port or would it be better to get a normal 0.075 gas port and run an adjustable gas block in the mean time?
Many barrel manufacturers are adapting to the market and closing their gas ports down to accommodate suppressor use. Criterion, Centurion. Geissele to name a few.
Personally I've never liked the idea of an adjustable gas block as I've seen more than a few break or get stuck. It's another point of failure for moderate returns.
Personally I've never liked the idea of an adjustable gas block as I've seen more than a few break or get stuck. It's another point of failure for moderate returns.
All my guns use adjustable gas blocks. I treat them like any moving part and service them occasionally. 34k rounds through three of them no issues
Depending on environmental and other conditions, I would expect function issues running unsuppressed with a 14.5" mid length gas ported at 0.063". With your varying configurations, I would go with a larger gas port and an AGB.
Both companies recommend a standard size gas port and use an AGB. One even mentioned a BRT gas tube as well
One thing I was also curious about is the Yankee Hill machine suppressor optimized gas block. I have no idea about it, but it did come up in some of my searches, so I was curious about that.
Until, earlier this year, the YHM blocks came with a 0.053" gas passage. They've since upped the passage to around 0.063" (might be 0.059", I can't remember). You can drill them out larger, and there is a hack to make the gas passage smaller, but neither the YHM or the BRT EZTune will give you the ability to tune your gas in the field without considerable hassle.
Yeah, I guess with carbon buildup and things like that, it could affect any tuning that could’ve been done prior. Because this rifle in the end will be using a suppressor only. So I thought I would just get it set up for using a suppressor and just leave it.
If you don't need to adjust the gas after initially tuning the gun you might as well just go with the BRT tuned gas tube and a fixed gas block. I have two rifles with their tubes and gas blocks. I pinned the gas blocks using their kit. Both guns set up suppressed. I'm really happy with this method. Tuned, simple, and pinned.
A lot of people seem to get confused on this issue, but the simple truth is that a "suppressor optimized" gas port provides exactly the same function as a single setting on an adjustable gas block. You can also install a restricting bushing in a normal gas block and accomplish the same thing too. All three of these are just methods of restricting gas flow at or immediately after the gas port.
The question remaining then is whether you want to be able to adjust the gas for your load, rifle, and suppressor, or go with what some manufacturer felt was best for their ammo and their suppressor. If you want to tune for ideal function with your own combination of equipment, then an AGB is generally the best route to go.
That doesn't mean the gas block has to stay adjustable after initial tuning. If you get it set right and it freezes up solid - great, that means it won't ever lose adjustment. Seems like a positive in my book, but many people point to that as a reason not to buy an adjustable gas block - pretty poor logic IMO.
I wouldn’t setup a rifle with a suppressor optimized gas port and fixed block just because I wouldn’t want to have function issues if I needed to shoot in unsuppressed. That’s ass backwards to me.
Even with an adjustable you can still tune the rifle with buffer weights as well and you can open the block all the way up and it will act just like a fixed
There’s no reason not to put an adjustable one on the gun with a gas port that will allow it to be fired suppressed or not
Even with an adjustable you can still tune the rifle with buffer weights as well and you can open the block all the way up and it will act just like a fixed
There’s no reason not to put an adjustable one on the gun with a gas port that will allow it to be fired suppressed or not
Personally I’m also of the opinion, if you have a can, unless you have multiple rifles for one can, why wouldn’t you only shoot suppressed?
Sometimes suppression isn't needed and the extra weight/length isn't warranted.
For example when I go hog hunting in the thickets I want my rifle to be as short as possible. Modern electronic ear protection like Sordins will guard my ears and can be comfortably worn all day.
Same here. Especially on higher pressure cartridges where the operating windows are smaller and the optimal gas settings are further apart from each other in the extremes
Personally I use my rifles for classes, or tactical games where they’re anal AF about muzzle devices, or the whole SHTF scenario everyone thinks about. I have a mk12 6 arc for hog/small game hunting right now and the ocm5 can easily be taken off(I don’t mind the gas too much with the fixed gas block) but I’ve never had experience with specific gas ports for specific use or underfunded gas blocks like the YHM, etc
