View Full Version : Best "long term" adjustable gas block?
Eurodriver
08-01-15, 20:16
I have a BCM 11.5" that I'd like to put an adjustable gas block on. The rifle just gets too "gassy" for my liking when suppressed. It has a LW barrel so a .625" gas block is needed.
I've heard many good things about Syrac. My main criteria is durability. I don't want to have to remove the rail and clean it every 500 rounds. That's like one day of shooting. I'd prefer to never have to clean it. Ease of adjustment and price are distant secondary criteria.
What works?
This also interests me, as I embark on my next build (10.5" Noveske AR Pistol). From the limited research I have done, adjustable GB are met with mixed reviews.
BillyJack556
08-02-15, 12:57
I have an SLR series 6 Adj .625 gas block and am very satisfied.
Great design and top of the line.
Rayrevolver
08-02-15, 13:16
Based on member reviews I also have a .625 SLR gas block for a new barrel that is incoming.
https://www.m4carbine.net/showthread.php?152712-SLR-Rifleworks-Sentry-7-setscrew-adjustable-gas-block-review
If I needed a .750 gas block I would look real hard at the Govnah. Its a little heavy but seems like a no brainer with respect to durability. I asked if they were making a .625 Govnah and the short answer was no.
Eurodriver
08-02-15, 15:16
I have an SLR series 6 Adj .625 gas block and am very satisfied.
Great design and top of the line.
This post is useless.
I have a BCM 11.5" that I'd like to put an adjustable gas block on. The rifle just gets too "gassy" for my liking when suppressed. It has a LW barrel so a .625" gas block is needed.
I've heard many good things about Syrac. My main criteria is durability. I don't want to have to remove the rail and clean it every 500 rounds. That's like one day of shooting. I'd prefer to never have to clean it. Ease of adjustment and price are distant secondary criteria.
What works?
By any chance, do you know the gas port size of that barrel?
I've used a few linear adjustable gas blocks, but they aren't a long term part or affordable or compact.
Are you out of possible options that eliminate the use of more action mass?
I have been in a similar pursuit for a while, without good results. I am not sure a commercial model exists yet.
I know it may seem like I'm a MicroMOA fanboi, but I just really like their shit.
If you know your ideal gas port (and MicroMOA can help you figure that out), then this may be the ideal solution for you: http://micromoa.com/baby-govnah/
Rayrevolver
08-02-15, 18:59
I know it may seem like I'm a MicroMOA fanboi, but I just really like their shit.
If you know your ideal gas port (and MicroMOA can help you figure that out), then this may be the ideal solution for you: http://micromoa.com/baby-govnah/
Dood, he said .625" so Govnah and Baby do not work.
Sorry Euro, we are not being helpful. I posted the review of the SLR above. I like that there is no spring and detent, I hear they bind up. It uses a leaf spring instead that is serviceable.
Also, there is a flat so the set screw option can be drilled and pinned (don't know about the clamp version). Adco said they would pin it, that is my plan for a suppressed only upper.
BufordTJustice
08-02-15, 20:22
I have a BCM 11.5" that I'd like to put an adjustable gas block on. The rifle just gets too "gassy" for my liking when suppressed. It has a LW barrel so a .625" gas block is needed.
I've heard many good things about Syrac. My main criteria is durability. I don't want to have to remove the rail and clean it every 500 rounds. That's like one day of shooting. I'd prefer to never have to clean it. Ease of adjustment and price are distant secondary criteria.
What works?
Simple. I just installed an SLR .625" Sentry 6 Titanium set screw gas block on my Faxon 18" gunner profile barrel. About 700 rds through it so far. With their new black high temper (and high temp rated) detent spring, I couldn't recommend anything else.
I had several thousand (2.2k) through a previous generation Sentry 7 .750" set screw in SBN 4140 and it's still running strong. Just sold that to a buddy the other day.
The owner of SLR tests all his AGB's on suppressed setups as part of routine product development.
I couldn't dream up a bad thing to say about Syrac AGB's if I tried, but SLR has been working great for me.
Dood, he said .625" so Govnah and Baby do not work.
Sorry Euro, we are not being helpful. I posted the review of the SLR above. I like that there is no spring and detent, I hear they bind up. It uses a leaf spring instead that is serviceable.
Also, there is a flat so the set screw option can be drilled and pinned (don't know about the clamp version). Adco said they would pin it, that is my plan for a suppressed only upper.
Damn, I stand corrected. My mind went straight from thinking about .625s to the "simple" part of the deal and failed to return home.
Eurodriver
08-02-15, 20:39
Thanks for the info guys.
I know there are many folks with experience using adjustable gas blocks but I'm just looking for objective information such as "I have xxx number of suppressed rounds through it and I adjust the setting every xx rounds after switching to u suppressed use" etc etc
BufordTJustice
08-02-15, 21:15
Thanks for the info guys.
I know there are many folks with experience using adjustable gas blocks but I'm just looking for objective information such as "I have xxx number of suppressed rounds through it and I adjust the setting every xx rounds after switching to u suppressed use" etc etc
I just adjusted the Sentry 7 in the barrel I sold within the last 100 rounds i fired through it. Well over a thousand unsuppressed rounds (mostly federal xm193, with a few hundred rounds of tula 55gr) before the last adjustment before that.
No issues changing gas settings. It was a little sticky on the first movement, but by the second notch, it was normal. This was with the std temp leaf spring, not the newer high temp black spring.
That's all I got. Lol.
I've been using an SLR on my 10.5 Wolf Pup. I don't know how many rounds I've got through it, but it's several hundred and it's not babied. No suppressor. I've never had the adjuster seize up and it always turns without undue effort, but I do occasionally hit the leaf spring and set screw with a little Frog Lube. It works good enough with a standard carrier and works even better with an LMT enhanced carrier. There is carbon fouling around the gas block which is evidence the gas block leaks a little through the three slots of the set screw and from around the leaf spring. However, I can't say the leakage has ever affected reliability
BufordTJustice
08-02-15, 22:21
This picture is after about 180 rounds. The recently improved adjustment screw has very little leakage. This is actually the std spring. I bought mine a week prior to the black spring release. SLR sent me a free black spring anyway.
http://images.tapatalk-cdn.com/15/08/02/5234131ebd91c161a1dacfc8b205ea7e.jpg
I have a BCM 11.5" that I'd like to put an adjustable gas block on. The rifle just gets too "gassy" for my liking when suppressed. It has a LW barrel so a .625" gas block is needed.
I've heard many good things about Syrac. My main criteria is durability. I don't want to have to remove the rail and clean it every 500 rounds. That's like one day of shooting. I'd prefer to never have to clean it. Ease of adjustment and price are distant secondary criteria.
What works?
Are you wanting to adjust gas up and down or do you really just want a smaller fixed gas port?
Those are two different but related things.
Markm used our CustomTune Gas Ports with good success on his 11.5" upper that had a huge gas port.
These thread into your existing gas block or FSB and are available in a variety of sizes.
The .070" is great for normal / mixed use and .060" for dedicated suppressed use.
Once installed, there are no moving parts and there is nothing that needs maintenance or cleaning, just like an original factory gas port.
Eurodriver
08-03-15, 07:12
Again, thanks for all of the info guys.
I previously owned a dedicated suppressed AR. It was a 16" carbine cut to 10.3" without gas port work. Unfortunately it would not function unsuppressed. I do not want to go down that road again and that is the reason I bought the 11.5" BCM in the first place.
I want adjustability, but I'll settle on a fixed product if I can just get this gas out of my face. This never used to bother me because my shooting was done outdoors while moving and around a breeze but due to my hectic schedule lately I've had to do some gun fun indoors and it is downright painful to shoot more than a few rounds suppressed
The goal is to stop the gas, and have the rifle remain functional unsuppressed and suppressed. Whether that is done by an AGB or a method of stopping the gas from seeping out of the upper and into my eyes is irrelevant to me. Reliability is paramount, however.
jerrysimons
08-03-15, 08:18
I think Syrac and SLR Rifleworks especially, would both be up for the task. SLRs design has got to be the most robust out right now.
My BCM 11.5" has a .076" gas-port.
Eurodriver, I suggest you combine the adjustable gas block with the LMT enhanced carrier. Tested back to back in 10.5 inch upper, my initial findings are that the LMT Enhanced Carrier allows for finer tuning and operates with less gas than a standard carrier
I'm not convinced that choking down the gas port flow, by whatever means, will reduce gassiness. I don't have a wide sample to draw from. But it seems I can still remember a certain amount of gas.. even when tuned to dedicated suppressed levels.
A certain amount of gas will still flow out of the chamber and ejection port. If you ever pull the bolt/bolt group on a recently fired suppressed barrel, you'll notice that you can't even see down the bore because of the thick, nasty gas lingering in the barrel.
Eurodriver
08-03-15, 11:26
If that's true, then what is the best way to eliminate the gas that gets in your eyes when firing suppressed? Aside from the normal "It doesn't bother me", "suck it up", "don't be a pussy", etc?
BufordTJustice
08-03-15, 11:29
If that's true, then what is the best way to eliminate the gas that gets in your eyes when firing suppressed? Aside from the normal "It doesn't bother me", "suck it up", "don't be a pussy", etc?
LMT e-carrier, Vltor A5H4 buffer, Sprinco Green spring, and whatever gas settings work with that combo.
Rayrevolver
08-03-15, 12:09
I did this mod while waiting for the suppressor, so I cannot speak to shooting suppressed without it.
Cheap and easy, might as well give it a shot.
http://www.03designgroup.com/technotes/do-it-yourself-gas-buster-charging-handle
BillyJack556
08-03-15, 12:25
This post is useless.
Can the attitude slick. You asked what works and I told you, SLR's.
Insulting someone who was trying to help instead of simply ignoring the post belittles yourself not me.
I'm not convinced that choking down the gas port flow, by whatever means, will reduce gassiness. I don't have a wide sample to draw from. But it seems I can still remember a certain amount of gas.. even when tuned to dedicated suppressed levels.
A certain amount of gas will still flow out of the chamber and ejection port. If you ever pull the bolt/bolt group on a recently fired suppressed barrel, you'll notice that you can't even see down the bore because of the thick, nasty gas lingering in the barrel.
It may not help compared to an AR properly ported to run suppressed, but it's much better than running a suppressed AR that's over gassed. And if the LMT carrier will run on less gas and opens the bolt even a fraction of a second later, the shooter can take full advantage of an adjustable gas block
My observations over the years seems to indicate that the when using different cans is that the amount of gas drive to the action system and blowback of fouling in different cans are not the same. Cans can produce many different attributes besides sound quality. Some cans blowback more without needing as much in a change in action system weight to maintain the balance of operation. I would tend towards looking at a sound suppression systems with a lower degree of lower pressure fouling coming back, given the same or similar span of operation. That is as long as it doesn't hamper the duration or span in function of a particular setup.
The lower pressure blowback can't be eliminated with current technology, but there are some things that can be done to reduce that in the commercial market.
I couldn't dream up a bad thing to say about Syrac AGB's if I tried, but SLR has been working great for me.
I can. I put a Syrac Gen II .750 on a 11.5" barrel with a .073 gas port. After approximately 200 rounds through the gun with a 556-SD suppressor I noticed that the detent screw was spinning freely. I attempted to apply solvent to the threads and vent port but this did no good. At that point I attempted to contact Syrac customer service through their website but was ignored. This was only the most recent episode of Syrac ignoring my attempts to obtain customer service. They seem from my experience to have a bad habit of not picking up the phone or answering emails, which is an unfortunate outlier in the current market. I took the block off the barrel and tried to clean it, but this was futile. At that point I felt I had to diagnose the problem myself. I knocked the pin out of the port and found that the spring was fused in place with caked fouling. I was able to remove the spring after a soak in some solvent and scraped the fouling loose, but was unable to recover the detent. I carefully backed the screw out, but still could not recover the detent. I really do not understand what could have happened to it because I certainly was not being Cavalier when I backed out the screw. Perhaps it was lost in the caked fouling? This is basically irrelevant, though, because I would never trust this device again after such a troubling premature failure.
I replaced it with a SLR Sentry, which so far has worked as advertised and in my opinion should be much less prone to this kind of failure given the design. SLR even replied to my email within an hour when I asked a question.
This experience has left me with a $100 paper weight. Caveat Emptor.
Fatorangecat
08-04-15, 00:52
I can. I put a Syrac Gen II .750 on a 11.5" barrel with a .073 gas port. After approximately 200 rounds through the gun with a 556-SD suppressor I noticed that the detent screw was spinning freely. I attempted to apply solvent to the threads and vent port but this did no good. At that point I attempted to contact Syrac customer service through their website but was ignored. This was only the most recent episode of Syrac ignoring my attempts to obtain customer service. They seem from my experience to have a bad habit of not picking up the phone or answering emails, which is an unfortunate outlier in the current market. I took the block off the barrel and tried to clean it, but this was futile. At that point I felt I had to diagnose the problem myself. I knocked the pin out of the port and found that the spring was fused in place with caked fouling. I was able to remove the spring after a soak in some solvent and scraped the fouling loose, but was unable to recover the detent. I carefully backed the screw out, but still could not recover the detent. I really do not understand what could have happened to it because I certainly was not being Cavalier when I backed out the screw. Perhaps it was lost in the caked fouling? This is basically irrelevant, though, because I would never trust this device again after such a troubling premature failure.
I replaced it with a SLR Sentry, which so far has worked as advertised and in my opinion should be much less prone to this kind of failure given the design. SLR even replied to my email within an hour when I asked a question.
This experience has left me with a $100 paper weight. Caveat Emptor.
I cannot say enough good about SLR's customer service. I had a gunsmith mangle a Sentry during a refinishing job and SLR went above and beyond to replace components at no cost even though it had nothing to do with them. They even payed the shipping.
I think SLR and Syrac are good companies with good cs, but I had failures with adjustable blocks from both. I'll try to post more later but IMHO screw adjusters just aren't the right design for reliability. These products serve a certain market and purpose but personally I wouldn't rely on them if reliability is a priority for the gun.
I think SLR and Syrac are good companies with good cs, but I had failures with adjustable blocks from both. I'll try to post more later but IMHO screw adjusters just aren't the right design for reliability. These products serve a certain market and purpose but personally I wouldn't rely on them if reliability is a priority for the gun.
Failed?
How can a Syrac gas block fail?
Singlestack Wonder
08-04-15, 09:12
With any adjustable gas block, the adjustment mechanism will lock up due to carbon fouling and require soaking/cleaning to restore operation. Of course, once the right adjustment is found, most never change the settings.
Failed?
How can a Syrac gas block fail?
Detent siezed and adjustment screw no longer had detents to hold the adjustment. So the adjustment could move on it's own and it was hard to set the adjustment without detent clicks.
Or if the adjustment in on the rear of the block. Much easier if it's on the front.
With any adjustable gas block, the adjustment mechanism will lock up due to carbon fouling and require soaking/cleaning to restore operation. Of course, once the right adjustment is found, most never change the settings.
I wouldn't consider a maintenance issue as a failure of the part. I hit my adjustment screws with a drop of Kroil before and after each use and my Syrac's have never locked up.
Sparky5019
08-04-15, 18:24
I've had 6 Syracs and each one locked up solid. The ones on the suppressed guns didn't make 1000 rounds before they were done. Don't get me wrong, it's a well made block but if you're putting more than 100 rounds in a session through the rifle, it will not last. It definitely won't make through a class without locking up.
I use SLR blocks in all our builds. A little SLiP2000 EWL on the adjustment screw and it will be free. They recommend when you clean the rifle to run the screw closed then back open to its prior position. That will help to keep it free.
The big deal with AGBs is where the gas you cut off from going back into action is vented. Everything good thing has consequences. The SLR provides for this and the Syrac does not. Consequently, that gas goes into the Syrac's mechanism causing it to foul up and seize in short order especially since the Syrac has such a fine adjustability. The SLR has a more coarse adjustment mechanism that handles this fouling better.
If you plan to set it and NEVER move it, a Syrac or other Swiss watch type block might work...but if you EVER MIGHT change it (think about changing ammo in a pinch), then get a SLR. It's a very well thought out and well made block.
I shot 1000 rounds through my suppressed 10.3" last week without cleaning the rifle and the adjustment screw is as free as the day I installed it.
Disclaimer: no affiliation with SLR but I'll never by another brand AGB again...EVER.
Just sayin.
Sparky5019
08-04-15, 18:58
If that's true, then what is the best way to eliminate the gas that gets in your eyes when firing suppressed? Aside from the normal "It doesn't bother me", "suck it up", "don't be a pussy", etc?
A buddy of mine played with the adjustable gas keys also. I'm not sure that playing with the system on the low pressure end is any better. He shot several thousand rounds through them with mixed results. The major problem was getting the screws to stay set even with loctite.
I'd honestly go with a block over a key. To me, adjusting on the high pressure end lends to more reliability and less gas physically going into the action (even if it lingers in the barrel and chameet, it ain't moving), less carrier velocity and less gas in the face. Adjusting on the low pressure end lends to the need for a minute adjustment or maladjustment that can make a huge difference in reliability.
The upside to a block over a key is that you can choose the buffer and spring that YOU want and tune the gun to it, especially suppressed. My MK18 shoots like a friggin wet dream instead of an over gassed beast that I had to buffer and spring down.
YMMV.
Too bad pws hasn't made a DI version of their piston adjustable. gas block. That thing is pretty slick. Never frozen, and easy to adjust.
Not that it really helps, just talking outloud and to myself.
BufordTJustice
08-04-15, 19:57
I've had 6 Syracs and each one locked up solid. The ones on the suppressed guns didn't make 1000 rounds before they were done. Don't get me wrong, it's a well made block but if you're putting more than 100 rounds in a session through the rifle, it will not last. It definitely won't make through a class without locking up.
I use SLR blocks in all our builds. A little SLiP2000 EWL on the adjustment screw and it will be free. They recommend when you clean the rifle to run the screw closed then back open to its prior position. That will help to keep it free.
The big deal with AGBs is where the gas you cut off from going back into action is vented. Everything good thing has consequences. The SLR provides for this and the Syrac does not. Consequently, that gas goes into the Syrac's mechanism causing it to foul up and seize in short order especially since the Syrac has such a fine adjustability. The SLR has a more coarse adjustment mechanism that handles this fouling better.
If you plan to set it and NEVER move it, a Syrac or other Swiss watch type block might work...but if you EVER MIGHT change it (think about changing ammo in a pinch), then get a SLR. It's a very well thought out and well made block.
I shot 1000 rounds through my suppressed 10.3" last week without cleaning the rifle and the adjustment screw is as free as the day I installed it.
Disclaimer: no affiliation with SLR but I'll never by another brand AGB again...EVER.
Just sayin.
Pre treating the screw with FireClean goes a LONG way toward that end.
Sparky5019
08-04-15, 20:16
Pre treating the screw with FireClean goes a LONG way toward that end.
With the Syrac blocks, I treated them all with Frog Lube prior to use then reapplied intermittently. No joy. I know FL and FC are not the same but still similar. As always, YMMV.
Too bad pws hasn't made a DI version of their piston adjustable. gas block. That thing is pretty slick. Never frozen, and easy to adjust.
Not that it really helps, just talking outloud and to myself.
I've seen a couple get pretty damn difficult to move (including my own). Ended up bending the nipple on the adjustment tool...
BufordTJustice
08-05-15, 07:40
With the Syrac blocks, I treated them all with Frog Lube prior to use then reapplied intermittently. No joy. I know FL and FC are not the same but still similar. As always, YMMV.
Wow. Well, you did what you could.
Sparky5019
08-05-15, 08:59
Wow. Well, you did what you could.
I'm convinced that it's the venting issue. The Syrac is a very well made block but the mechanism is just too fine to allow the blocked gas to vent through without consequently getting extremely dirty.
Let's be real though...if you ignore any AGB, it will eventually lock up from fouling.
I've seen a couple get pretty damn difficult to move (including my own). Ended up bending the nipple on the adjustment tool...
Really? That kinda sucks. I'm about 3k rounds down the barrel on that rifle and good far, but we all know that doesn't mean Jack. I try to cycle it a few times a year.
Eurodriver
08-06-15, 03:12
So what is the consensus?
I just want a gas block that will last for a long time without requiring maintenance. I don't mind once every 500-1000 rounds having to lube it, but I want it to be something I do as a precaution, not a requirement.
It sounds like the SLR is the go to choice comparatively, but is it worth ditching the OEM gas block?
Singlestack Wonder
08-06-15, 08:25
If its a matter of taming down an overgassed 7.62, typically the block is adjusted and never changed again. For 5.56 suppressor use where one will turn down the gas when using a suppressor and turn it back up when not, the best option is a Noveske Switchblock. Carbon deposits will always happen, and adjustable gas blocks will always be problematic (unless set once and never changed).
Sparky5019
08-06-15, 08:32
So what is the consensus?
I just want a gas block that will last for a long time without requiring maintenance. I don't mind once every 500-1000 rounds having to lube it, but I want it to be something I do as a precaution, not a requirement.
It sounds like the SLR is the go to choice comparatively, but is it worth ditching the OEM gas block?
My answer is unequivocally YES!
Lots of anecdotal failure stories. An #8-32 set screw in an #8-32 set screw. Not sure how one variant of GB can have more precision threads than the other. If your going argue that they can, please document that there is a difference between the two GB's.
Sparky5019
08-06-15, 10:45
Lots of anecdotal failure stories. An #8-32 set screw in an #8-32 set screw. Not sure how one variant of GB can have more precision threads than the other. If your going argue that they can, please document that there is a difference between the two GB's.
Considering they're 10-32 actually there is a lot of difference. The SLR uses slightly oversized threads in the block so that vented gas and fouling is released and doesn't foul the threads to the point of seizing. Syrac is standard thread mating and makes no such allowance.
Considering they're 10-32 actually there is a lot of difference.
Really? The set screw in my Sentry 9 is clearly an #8-32.
34531
The SLR uses slightly oversized threads in the block so that vented gas and fouling is released and doesn't foul the threads to the point of seizing.
How oversized? Half a ten, three thousandths? Interesting claim considering this statement from SLR's website... "100% Gas seal allows full cut off and prevents gas from fouling metering screw"
Syrac is standard thread mating and makes no such allowance.
I don't doubt this to be the case because there is no valid reason to do it any other way. Encouraging gas to vent through the threads doesn't make sense.
If the Syrac model does have a higher rate of seizure compared to the SLR, it's likely due to the difference in the detent mechanism. The Syrac model indexes every 90 degrees compared to the SLR at 120. To accomplish this, the Syrac has to use a very small bearing compared to a larger custom detent in the SLR.
34532
Sparky5019
08-07-15, 09:42
Ok. We are talking 5.56 block so in the Sentry 6 and 7 series. I don't do AR-10 crap so I'm not going to comment on that block.
The description of the thread sizing was from a personal conversation with the designer of the SLR block. I believe the seal referred to not he website is the gas chamber and very tip of the screw because people were bitching about not being yo cut off the gas completely and turn there rifle into a bolt gun. Whatever. During that conversation, I asked about seizure and how they prevent it. He explained the thread sizing. It's not a matter of how many thou the hole threads are oversized as much as thread sizes have many within a std designation size (8-32, etc.). This allows for slight tolerance across production and tooling. These are typically designated by "NC" and a number following the thread size (8-32 NC 1). Our conversation did not go that in depth but he stated that they made the hole threads "size larger" to vent that gas and went farther to say if you look closely at some high round count barrels beneath the screw, you might see the "trail" that the vented excess gas leaves.
Syrac's adjustment mechanism is a COTS mechanism in that the bearing and spring are installed in that hole to do the job. They're not purpose designed for the job. Do they work? Yes. Is it subject to failure? Yes, as we've seen. The screw that Syrac is using looks like an altered COTS part as well. I'm not saying it doesn't work but it's certainly not optimal as we've seen many that seize under moderate round count use.
Another thing I noticed is that the Syrac blocks that I've installed on high quality barrels like BCM and Daniel Defense were loose and were leaking between the bkock and the barrel. When contacted, both the barrel makers and Syrac blamed the other. I even taper pinned a couple of Syracs in hopes of getting a better seal. No joy. The SLR has given zero problems in this regard.
As far as adjustment, I initially thought more options were better however when you take into account suppressor use and a dirty action as well as the vast choices and quality of lubes used, I have reversed my initial opinion. A gun that run clean at one setting usually won't run dirty on that same setting IF it was on the edge to start with.
I may have mis stated the thread size as I did not measure it but just recalled it from the conversation. I'm speaking from my experience and the discussions that I've had with SLR and all of my guys who are using that block. I've had similar discussions with Syrac and the response was to the effect of "here it is, if you like it, buy it, if not ok". They're very nice people that's just the way they see it.
I think SLR prefers the coarse adjustment for various reasons because I'm sure they could put a smaller nose radius on their detent and get a finer adjustment. I actually asked him about that and he stated that they found it wasn't really necessary to have that fine an adjustment.
Like I said. YMMV. I was contributing my experience to the discussion. That's it. That's all.
Have a fabulous day.
Anyone try the micromoa govnah ? (www.micromoa.com) I have one, looks good, but have not been able to do any real testing. No screw to foul/erode, quick adjustment to alternate settings.
Sparky5019
08-07-15, 19:33
Anyone try the micromoa govnah ? (www.micromoa.com) I have one, looks good, but have not been able to do any real testing. No screw to foul/erode, quick adjustment to alternate settings.
I have not. It struck me as the other extreme; not enough adjustment plus the design looked heavy, cumbersome and unreliable in a rough situation (dropped rifle or some other roughness).
JMHO.
I've used the govnah some and I prefer it to any screw adjustment type. But adjustable gas blocks have a specific purpose to me: to allow *selecting* a more suitable gas feed for both suppressed and unsuppressed configurations. If I were to just pick a setting on a screw adjustment and then leave it there, I'd just go with a fixed port gas block and enlarge the port until I was satisfied. This is because its cheaper, but more importantly because there's no mechanism to fail. If I want to switch between suppressed and not, with different settings for each, then an adjustment method with fixed positions is preferable. That's one reason why I prefer the govnah for that situation. It just so happens that I also think it's going to be more reliable, and so far it is for me.
Yes, the govnah is slightly heavier than a standard LP gas block...I don't care, someone else might be worried about that relatively small weight addition though. Cumbersome...I just can't agree with that at all. It uses either a two position or three position plate with no need for tools. I guess with *some* handguards the plate might not line up perfectly with a slot for the easiest access, and I used the govnah with one such hanguard but I still didn't find it cumbersome to change the setting. As far as reliability goes...while I'd really rather not have the additional parts in the gas block anyway, I think the govnah design is a LOT more reliable than the screw adjustment types. I'm not sure how dropping the rifle would cause a problem with the govnah gas block unless it was exposed, in which case yeah, the detent spring could get snagged and pulled which would cause a problem...so don't have it exposed.
In the end it all comes down to your planned use and priorities. I personally still don't trust any adjustable block completely and my go to carbines don't have 'em. I need to get some more rounds through the govnah but to me it's the best adjustable gas block option that fits under a handguard. My Syrac seized the detent in about 500 rds and I couldn't change to my "suppressed" setting as a result. No detents so I didn't know where to set it and didn't know if it would even stay there anyway. My SLR blew it's guts out the side (well, the detent anyway) in even less rounds and the adjuster starting self-adjusting and causing all kinds of drama with the gun. I will say that I *think* the root cause of the SLR failure was a manufacturing defect that was likely to result in a failure early in it's life, so if one makes it several hundred rounds it probably isn't going to fail in the way mine did. Am I doing something to cause these failures? I know what my answer is to that but I'm sure someone can come up with some way it's my fault....whatever, if the things are that damn finicky then I won't depend on 'em. Sorry if it sounds like bashing but I really do think the companies are good, I just don't think much of that style of gas block.
I didnt read the whole thread, micromoa was brought up, then dq'ed because its not .625 sorry OP.
Eurodriver
08-08-15, 07:25
I didnt read the whole thread, micromoa was brought up, then dq'ed because its not .625 sorry OP.
It's ok. Unfortunately the nature of the Internet is that people would rather argue than actually do anything helpful.
Sparky5019
08-08-15, 10:37
I've used the govnah some and I prefer it to any screw adjustment type. But adjustable gas blocks have a specific purpose to me: to allow *selecting* a more suitable gas feed for both suppressed and unsuppressed configurations. If I were to just pick a setting on a screw adjustment and then leave it there, I'd just go with a fixed port gas block and enlarge the port until I was satisfied. This is because its cheaper, but more importantly because there's no mechanism to fail. If I want to switch between suppressed and not, with different settings for each, then an adjustment method with fixed positions is preferable. That's one reason why I prefer the govnah for that situation. It just so happens that I also think it's going to be more reliable, and so far it is for me.
Yes, the govnah is slightly heavier than a standard LP gas block...I don't care, someone else might be worried about that relatively small weight addition though. Cumbersome...I just can't agree with that at all. It uses either a two position or three position plate with no need for tools. I guess with *some* handguards the plate might not line up perfectly with a slot for the easiest access, and I used the govnah with one such hanguard but I still didn't find it cumbersome to change the setting. As far as reliability goes...while I'd really rather not have the additional parts in the gas block anyway, I think the govnah design is a LOT more reliable than the screw adjustment types. I'm not sure how dropping the rifle would cause a problem with the govnah gas block unless it was exposed, in which case yeah, the detent spring could get snagged and pulled which would cause a problem...so don't have it exposed.
In the end it all comes down to your planned use and priorities. I personally still don't trust any adjustable block completely and my go to carbines don't have 'em. I need to get some more rounds through the govnah but to me it's the best adjustable gas block option that fits under a handguard. My Syrac seized the detent in about 500 rds and I couldn't change to my "suppressed" setting as a result. No detents so I didn't know where to set it and didn't know if it would even stay there anyway. My SLR blew it's guts out the side (well, the detent anyway) in even less rounds and the adjuster starting self-adjusting and causing all kinds of drama with the gun. I will say that I *think* the root cause of the SLR failure was a manufacturing defect that was likely to result in a failure early in it's life, so if one makes it several hundred rounds it probably isn't going to fail in the way mine did. Am I doing something to cause these failures? I know what my answer is to that but I'm sure someone can come up with some way it's my fault....whatever, if the things are that damn finicky then I won't depend on 'em. Sorry if it sounds like bashing but I really do think the companies are good, I just don't think much of that style of gas block.
I actually like the concept and I think LaRue executed a switch type block the best. I have found the need for more than 2 or 3 settings so that's the reason for my preference.
BufordTJustice
08-08-15, 10:58
I've used the govnah some and I prefer it to any screw adjustment type. But adjustable gas blocks have a specific purpose to me: to allow *selecting* a more suitable gas feed for both suppressed and unsuppressed configurations. If I were to just pick a setting on a screw adjustment and then leave it there, I'd just go with a fixed port gas block and enlarge the port until I was satisfied. This is because its cheaper, but more importantly because there's no mechanism to fail. If I want to switch between suppressed and not, with different settings for each, then an adjustment method with fixed positions is preferable. That's one reason why I prefer the govnah for that situation. It just so happens that I also think it's going to be more reliable, and so far it is for me.
Yes, the govnah is slightly heavier than a standard LP gas block...I don't care, someone else might be worried about that relatively small weight addition though. Cumbersome...I just can't agree with that at all. It uses either a two position or three position plate with no need for tools. I guess with *some* handguards the plate might not line up perfectly with a slot for the easiest access, and I used the govnah with one such hanguard but I still didn't find it cumbersome to change the setting. As far as reliability goes...while I'd really rather not have the additional parts in the gas block anyway, I think the govnah design is a LOT more reliable than the screw adjustment types. I'm not sure how dropping the rifle would cause a problem with the govnah gas block unless it was exposed, in which case yeah, the detent spring could get snagged and pulled which would cause a problem...so don't have it exposed.
In the end it all comes down to your planned use and priorities. I personally still don't trust any adjustable block completely and my go to carbines don't have 'em. I need to get some more rounds through the govnah but to me it's the best adjustable gas block option that fits under a handguard. My Syrac seized the detent in about 500 rds and I couldn't change to my "suppressed" setting as a result. No detents so I didn't know where to set it and didn't know if it would even stay there anyway. My SLR blew it's guts out the side (well, the detent anyway) in even less rounds and the adjuster starting self-adjusting and causing all kinds of drama with the gun. I will say that I *think* the root cause of the SLR failure was a manufacturing defect that was likely to result in a failure early in it's life, so if one makes it several hundred rounds it probably isn't going to fail in the way mine did. Am I doing something to cause these failures? I know what my answer is to that but I'm sure someone can come up with some way it's my fault....whatever, if the things are that damn finicky then I won't depend on 'em. Sorry if it sounds like bashing but I really do think the companies are good, I just don't think much of that style of gas block.
Just curious, but were you using the melonited detent with the new black high-temp leaf spring, or was it the original spring with the non melonited detent?
The high temp spring came out about a month and a half ago.
I really don't care for adjustable gas blocks on any AR that may see any serious use. If it's just a fun game gun, have at it, have fun and deal with the possible issues. I really prefer dedicated porting, and maybe a buffer swap with a can if needed. I've worked with a few generally over gassed AR's in the past that were tamed down by use of a specifically made inconel insert in the gas block.
jerrysimons
08-08-15, 20:51
So why do ADJ need to vent gas? Is it just that they will vent gas through the United sealed threads because the pressure takes the path of least resistance so some companies (SLRR) accommodate for it? Or is it more like they need to vent the gas. Why can't it just be choked off and the excess go back through the barrel like Black River Tactical's gas port insert would do?.
I have not. It struck me as the other extreme; not enough adjustment plus the design looked heavy, cumbersome and unreliable in a rough situation (dropped rifle or some other roughness).
JMHO.
I recently purchased a Govnah with the 3 position plate, and I just drilled the plates to allow a suppressed/un-suppressed/adverse style of adjustment. Im curious, how do you use than 3 gas settings at any given time?
I've been told the Govnah will not move, even if dropped. So far, I dont see how it could. It takes more effort that I expected to move the plate. I'll find out soon enough tho. Starting next month my Govnah equipped Reece will be bouncing around in the trunk of my squad car to see what happens.
Sparky5019
08-09-15, 07:43
So why do ADJ need to vent gas? Is it just that they will vent gas through the United sealed threads because the pressure takes the path of least resistance so some companies (SLRR) accommodate for it? Or is it more like they need to vent the gas. Why can't it just be choked off and the excess go back through the barrel like Black River Tactical's gas port insert would do?.
Physics tells us that there's no free lunch. If you decrease the amount that goes into the gas tube the rest must go somewhere. The real issue is how much gas the port lets out if the bore. If it lets out 20% more than is necessary to operate the action then the block has to vent the other say 18% that is not required to run the action.
The BRT solution is exactly the same as an AGB except it permanent and doesn't have the adjustment issue. If you were to disassemble one of those, you would find it very dirty and possible seized into its position. It does provide a solution to the over gassed rifle but it's a single size solution. I've used them, they're great for FSBs that have no adjustment option.
The problem here is how much gas the port allows to leave the bore. If you tune it down, you'll have to deal with where the excess will vent.
The adjustable gas block for the AR does not have to vent gas at all. It only has to restrict gas flow. The rest of the gas is vented through the muzzle.
If we were talking about the FAL gas regulator, that would be another story. The FAL regulator works by controlling how much gas it vents at the block, not by restriction
jerrysimons
08-09-15, 10:06
The adjustable gas block for the AR does not have to vent gas at all. It only has to restrict gas flow. The rest of the gas is vented through the muzzle.
If we were talking about the FAL gas regulator, that would be another story. The FAL regulator works by controlling how much gas it vents at the block, not by restriction
This is kind of what I was thinking. So, it is just a matter of the path of least resistance when the excess pressure to blows down and the inherent design obstacle of an adjustable regulation mechanism using the threads of a screw susceptible to seizure, I gather?
Sparky5019
08-09-15, 12:02
The adjustable gas block for the AR does not have to vent gas at all. It only has to restrict gas flow. The rest of the gas is vented through the muzzle.
If we were talking about the FAL gas regulator, that would be another story. The FAL regulator works by controlling how much gas it vents at the block, not by restriction
You are correct but there's no free lunch. It does restrict the amount of gas allowed into the gas tube but what happens to the rest of the gas that leaves the gas port? The pressure gradient is too high for it to be forced back into the bore. Where is it supposed to go? If the restriction only solved the problem then the adjustment mechanisms wouldn't become fouled and seize up in certain cases.
This would also not explain why my (and others') left hand was black from gas escaping THROUGH the Syrac's adjustment mechanism on the left side of the block. Consistent with this venting, the SLR vents forward around the adjustment screw as mentioned.
The gas that does not escape the gas port is vented out the muzzle when bullet uncorks it but until then the pressure gradient between the gas tube at the gas block and the bore at the gas port is too great for reverse flow; it's a one way street. I think I read on AR-15 barrels that the port pressure on a 10.5" carbine gassed barrel is like 24,000 psi. I know that's only until the barrel is uncorked but that's still way too high to be anything but a one way street.
The way I see it is that you are correct in that the AGB is designed to restrict and not vent as foes the FAL block BUT the AGB must take into account that there needs to be a less restrictive path for the extra gas from the gas port that is bled off and not allowed down the gas tube. One thing we all forget occasionally (myself included) is that the gun is over gassed or there would be little need for an AGB (save for fine tuning suppressed guns).
I'm not a physicist but I can't construct any other reality on this one based on my experience with fouling and seizures; the path of the fouling is objective and consistent and doesn't suggest any other conclusion to me.
I've tried to provide the best info I can to help the collective here (Gid only knows how much y'all have helped me).
Good luck!
jerrysimons
08-09-15, 12:46
But theoretically speaking if it were possible for the adjustment mechanism to be sealed while restricting gas flow it would simply hold the pressure until the barrel pressure blew down enough to equalize and expell it out of the muzzle right? I fail to see how gas block insert regulation does not function this way with the exception of the seal between the barrel and gas block.
Sparky5019
08-09-15, 13:13
But theoretically speaking if it were possible for the adjustment mechanism to be sealed while restricting gas flow it would simply hold the pressure until the barrel pressure blew down enough to equalize and expell it out of the muzzle right? I fail to see how gas block insert regulation does not function this way with the exception of the seal between the barrel and gas block.
Theoretically, I think you're correct. The system would certainly have to be very tight. Honestly, I'm not even sure the block to barrel fit would be a problem as long as the block is not oversized. Once the bore is uncorked there would be very little to no pressure gradient so I would think said gas would just stop moving and not be an issue.
BufordTJustice
08-09-15, 13:36
Theoretically, I think you're correct. The system would certainly have to be very tight. Honestly, I'm not even sure the block to barrel fit would be a problem as long as the block is not oversized. Once the bore is uncorked there would be very little to no pressure gradient so I would think said gas would just stop moving and not be an issue.
This is part of the reason behind KACs new design using a type of castle nut to sandwich the gas block between the nut and the barrel gas block journal shoulder. Also, they use a different fitting to attach the gas tube to the gas block proper. It's basically as sealed as one can get.
Sparky5019
08-09-15, 13:49
This is part of the reason behind KACs new design using a type of castle nut to sandwich the gas block between the nut and the barrel gas block journal shoulder. Also, they use a different fitting to attach the gas tube to the gas block proper. It's basically as sealed as one can get.
Ooooh! I've not seen that. You really shouldn't have told me that. Lol. Thanks buddy! Now I'll have to check that out.
BufordTJustice
08-09-15, 15:30
Ooooh! I've not seen that. You really shouldn't have told me that. Lol. Thanks buddy! Now I'll have to check that out.
I'm here to help (you spend more money). ;)
jerrysimons
08-09-15, 15:36
Some observers after experimenting with carrier-key regulation have noticed excess gas from the pressurized gas-tube blowing out every which way it can from around the gas-tube hole/roll-pin and between the barrel and gas-block/front sight base more so than if pressure were not captured in the gas-tube.
So getting back to adjustable gas-block design limitations, in summary, the inherent venting of gas out of adjustment screw designs and the ensuing carbon fouling is the main reliability issue to contend with after designing a solid detent mechanism. Potential resulting issues include:
1.) seizure of the adjustment screw rendering the adjustablility of the GB useless and thus affecting reliability depending on the setting it seized at, the rifle's set-up (dwell time, gas port size, buffer weight, recoil spring, hammer spring, bcg, muzzle device back pressure, and suppressor), ammo used (556 vs .223), and firing conditions (air temp, dirty gun, etc.). This may not be an issue if the user's intention was to set it and forget it at a setting allowing a good margin of function (but then perhaps a gas-block insert like BRT offers is the best bet, imo)
2.) The spring detent mechanism may seize due to carbon fouling either resulting in the screw no longer moving which thus affects reliability as outlined in #1, or it may seize open which would render the detent useless and allow the adjustment screw to spin freely and even fall out, leaving the rifle deadlined.
It has been mentioned the spring detent design of the Syrac is susceptible to seizure as outlined in #2 because it is exposed to venting gas and the internal spring can be fouled inside it's hole. After messing with the the SLR Rifleworks design there is doubt the external leaf spring detent design is subject to this type of failure. It seems fatuige is the only thing it could be susceptible to but it is very stout and rated to >2000 degrees.
That gas will vent out of the adjustment screw is inevitable with the potential to seize the threads, all current adj gb using a screw are susceptible to failure #1 but SLRR has attempted to mitigate the effects of fouling by using looser fit thread tolerances that better accomodate the venting gas by creating more room for fouling in the threads to accumulate while still allowing for the screw to move.
It seems clear the best current adjustable gas-block design is the SLR Rifleworks Sentry series so long as one tends to the threads of the screw with Fireclean and by breaking the fouling free by twisting the screw back and forth every few hundred rounds. But is this suitable for a fighting rifle to avoid failure #1?
I think so, assuming a quality rail shrouds the GB, since likely the gas-block setting on a fighting rifle will already be set for an appropriate margine of function. However, for ultimate reliability under a "set it and forget it" mentality, a gas-block insert suitable to ones barrel length, gas system, and rifle set-up may be the best way to go. Albeit the insert requires more research as to which port size insert is best for the set up and more commitment upon installation.
My question for Clint is, will the gas block insert being made of stainless steel (Tom mentioned inconel) outlast a barrel in regards to erosion?
BufordTJustice
08-09-15, 16:05
Some observers after experimenting with carrier-key regulation have noticed excess gas from the pressurized gas-tube blowing out every which way it can from around the gas-tube hole/roll-pin and between the barrel and gas-block/front sight base more so than if pressure were not captured in the gas-tube.
So getting back to adjustable gas-block design limitations, in summary, the inherent venting of gas out of adjustment screw designs and the ensuing carbon fouling is the main reliability issue to contend with after designing a solid detent mechanism. Potential resulting issues include:
1.) seizure of the adjustment screw rendering the adjustablility of the GB useless and thus affecting reliability depending on the setting it seized at, the rifle's set-up (dwell time, gas port size, buffer weight, recoil spring, hammer spring, bcg, muzzle device back pressure, and suppressor), ammo used (556 vs .223), and firing conditions (air temp, dirty gun, etc.). This may not be an issue if the user's intention was to set it and forget it at a setting allowing a good margin of function (but then perhaps a gas-block insert like BRT offers is the best bet, imo)
2.) The spring detent mechanism may seize due to carbon fouling either resulting in the screw no longer moving which thus affects reliability as outlined in #1, or it may seize open which would render the detent useless and allow the adjustment screw to spin freely and even fall out, leaving the rifle deadlined.
It has been mentioned the spring detent design of the Syrac is susceptible to seizure as outlined in #2 because it is exposed to venting gas and the internal spring can be fouled inside it's hole. After messing with the the SLR Rifleworks design there is doubt the external leaf spring detent design is subject to this type of failure. It seems fatuige is the only thing it could be susceptible to but it is very stout and rated to >2000 degrees.
That gas will vent out of the adjustment screw is inevitable with the potential to seize the threads, all current adj gb using a screw are susceptible to failure #1 but SLRR has attempted to mitigate the effects of fouling by using looser fit thread tolerances that better accomodate the venting gas by creating more room for fouling in the threads to accumulate while still allowing for the screw to move.
It seems clear the best current adjustable gas-block design is the SLR Rifleworks Sentry series so long as one tends to the threads of the screw with Fireclean and by breaking the fouling free by twisting the screw back and forth every few hundred rounds. But is this suitable for a fighting rifle to avoid failure #1?
I think so, assuming a quality rail shrouds the GB, since likely the gas-block setting on a fighting rifle will already be set for an appropriate margine of function. However, for ultimate reliability under a "set it and forget it" mentality, a gas-block insert suitable to ones barrel length, gas system, and rifle set-up may be the best way to go. Albeit the insert requires more research as to which port size insert is best for the set up and more commitment upon installation.
My question for Clint is, will the gas block insert being made of stainless steel (Tom mentioned inconel) outlast a barrel in regards to erosion?
While I'm certainly biased, the SLR is the superior extant design because the spring is unlikely to become seized in the open position. Unless it were fired for many hundreds of rounds in between detents, not enough fouling could get under the spring to allow the screw to spin freely.
Again, a drop of FireClean from a needle oiler every 400 rounds or so is cheap insurance.
Besides, after 400 rounds with a can, there are other PM issues that need to be addressed on the weapon system as well. Like lubing the shit out of the BCG/CH/Bolt and the rest of the upper.
In terms of being "for a fighting rifle", one would do well to not change their weapon setup mid fight, or maybe they should set the AGB such that their gun will still run sans can if they need to remove it for some reason (I.e. it gets damaged, crushed, etc). Or, have a secondary weapon system to which one can transition.
Context is important in this discussion.
Sparky5019
08-09-15, 16:48
Good points gentlemen. My kudos to Jerry to putting in a nutshell what I can't put in a barrel without a bottom. Lol.
Singlestack Wonder
08-09-15, 17:14
Of course, not adding an adjustable gas block eliminates any and all problems associated with adjustable gas blocks.....
Agreed, dedicated porting is the better solution. Another less preferable possible solution to an over gassed example could be an insert in the gas block, given that the system doesn't leak excessively.
This is part of the reason behind KACs new design using a type of castle nut to sandwich the gas block between the nut and the barrel gas block journal shoulder. Also, they use a different fitting to attach the gas tube to the gas block proper. It's basically as sealed as one can get.
Ooooh! I've not seen that. You really shouldn't have told me that. Lol. Thanks buddy! Now I'll have to check that out.
Just to note, PWS has had a castle nut securing the gas block longer than Knight's. It launched with the MOD1 series. When I got my SR-15 MOD2 upper I said, "Cool, it has the same gas block securing method as my PWS MK2."
Also, the gas tube to block fitting on the MOD 2 is derived from liquid/gas fittings. I have a bunch of Swagelok ones at work.
jerrysimons
08-09-15, 23:21
Agreed, dedicated porting is the better solution. Another less preferable possible solution to an over gassed example could be an insert in the gas block, given that the system doesn't leak excessively.
Agreed, but how does one do this? It seems most manufactures lack the stones to put their name on something that might not function with Tula .223...
Also where did you get an inconel GB insert?
You are correct but there's no free lunch. It does restrict the amount of gas allowed into the gas tube but what happens to the rest of the gas that leaves the gas port?
You're over-thinking it. The gas simply follow the path of least resistance. If that path takes it from the gas port and through the restriction created by the adjustable gas block and down the gas tube, that's what it does. if the pressure in the bore drops enough, the gas will vent back into the bore.Gas flows through an adjustable block the same as it runs through a standard block.
The reason gas blows through the adjustment screw, out the gas tube roll pin and what have you is because are leak paths. It's higher pressure gas following the path of least resistance. If the gas block were perfectly sealed, the gas would't leak out at those points. And, as the AR adjustable gas block is restricting gas flow, there is no excess gas.
When the bullet uncorks the muzzle, the pressure does not just drop to nothing. It takes time for that gas to escape and vent. In fact, the gas system doesn't pressurize until after the bullet has exited. The gas system runs off of residual pressure
Agreed, but how does one do this?
Read this thread all the way through https://www.m4carbine.net/showthread.php?33743-Best-Suppressed-SBR-Ever
jerrysimons
08-10-15, 02:11
Read this thread all the way through https://www.m4carbine.net/showthread.php?33743-Best-Suppressed-SBR-Ever
I am familiar with this thread but Grant seems to have gotten a special order barrel from Noveske with a small gas port. I know SIONICS is testing "reduced" gas-port barrels for mixed suppressor use. Other than that the trend is for gapping gas ports, BCM and SIONICS current barrels are on the more conservative side of the industry, though.
Grant opened up the gas port a little at a time until he got the AR cycling the way he wanted. You will also note that the LMT Enhanced carrier proved to be crucial
Dan Ortego
08-10-15, 16:24
This interest me too. I recently ordered a Wilson and I asked them about their adjustable gas block. They told me their SR config comes with a tuned gas block that would run with or without their Whisper Suppressor and to leave it be. I was told if I ran clean quality ammo such as their match grade stock I could go thousands of rounds without cleaning. Sounded a bit too good to be true but we'll see.
Sparky5019
08-10-15, 16:27
You're over-thinking it. The gas simply follow the path of least resistance. If that path takes it from the gas port and through the restriction created by the adjustable gas block and down the gas tube, that's what it does. if the pressure in the bore drops enough, the gas will vent back into the bore.Gas flows through an adjustable block the same as it runs through a standard block.
The reason gas blows through the adjustment screw, out the gas tube roll pin and what have you is because are leak paths. It's higher pressure gas following the path of least resistance. If the gas block were perfectly sealed, the gas would't leak out at those points. And, as the AR adjustable gas block is restricting gas flow, there is no excess gas.
When the bullet uncorks the muzzle, the pressure does not just drop to nothing. It takes time for that gas to escape and vent. In fact, the gas system doesn't pressurize until after the bullet has exited. The gas system runs off of residual pressure
Lol. I know. I see what you're saying. Maybe a better way to put it would be that SLR has taken the leaks into account when designing their block do it leaks in a way that allows it to remain reliable and not seize up. I was thinking more into pressure gradients than path of least resistance. Thanks for bringing my ass back to earth. Lol.
Just to note, PWS has had a castle nut securing the gas block longer than Knight's. It launched with the MOD1 series. When I got my SR-15 MOD2 upper I said, "Cool, it has the same gas block securing method as my PWS MK2."
Also, the gas tube to block fitting on the MOD 2 is derived from liquid/gas fittings. I have a bunch of Swagelok ones at work.
Look at SR-25's from the '90s, then tell me who came up with the method, KAC or PWS.
Just curious, but were you using the melonited detent with the new black high-temp leaf spring, or was it the original spring with the non melonited detent?
The high temp spring came out about a month and a half ago.
Sorry...been away for a bit. The block in question was older so it wasn't the latest iteration. Not sure which gen it was though.
BufordTJustice
08-10-15, 21:05
Sorry...been away for a bit. The block in question was older so it wasn't the latest iteration. Not sure which gen it was though.
Gotcha. Thanks for taking the time to respond, brother.
ive been following this thread with some interest...I wouldnt mind trying the Govnah block but alittle intimidated about messing with all the different plates to find the right one..its easier on a block like SLR...HOwever even SLR blocks arent invincible...I've had 5 fail in the last year...all from various generations....
The good thing is that SLR is constantly trying update the design and the CS is great! BUT in the end...an adjustable gas block with these types of design will never be approved to be put on any military issued gun.
Interms of set it and forget it...When I have my SLRs set at a minimal average opeining for most my ammo...I dont have to close it any further when shooting suppressed. Ive shot close to 200 rounds with no jams yet and brass isnt torn up. All with a standard BCG and buffer on my 556 and grendel.
Nothing would beat a Noveske Switch block type of gas block but they are severely limited in fine tuning the gas....As well as the bulk that prevents it to be used in many of the narrow profile handguards today.
jerrysimons
08-19-15, 12:18
ive been following this thread with some interest...I wouldnt mind trying the Govnah block but alittle intimidated about messing with all the different plates to find the right one..its easier on a block like SLR...HOwever even SLR blocks arent invincible...I've had 5 fail in the last year...all from various generations....
The good thing is that SLR is constantly trying update the design and the CS is great! BUT in the end...an adjustable gas block with these types of design will never be approved to be put on any military issued gun.
Interms of set it and forget it...When I have my SLRs set at a minimal average opeining for most my ammo...I dont have to close it any further when shooting suppressed. Ive shot close to 200 rounds with no jams yet and brass isnt torn up. All with a standard BCG and buffer on my 556 and grendel.
Nothing would beat a Noveske Switch block type of gas block but they are severely limited in fine tuning the gas....As well as the bulk that prevents it to be used in many of the narrow profile handguards today.
Can you describe the failures of your SLR Rifleworks gas blocks what generation they were and what set up they were used with? Thanks
I think I am going to try one of the 2A Armament lightweight gas adjustable carriers when they come out in around a month. The links below have some info on them.
http://www.ar15.com/forums/t_2_493/259011_Lightweight_Patent_Pending_gas_adjustable_carrier.html
http://www.ar15.com/forums/t_2_493/258846_A_few_images_of_one_of_TWO_lightweight_carriers_coming_out_soon_.html
ive been following this thread with some interest...I wouldnt mind trying the Govnah block but alittle intimidated about messing with all the different plates to find the right one..its easier on a block like SLR...HOwever even SLR blocks arent invincible...I've had 5 fail in the last year...all from various generations....
For the Govnah, start with the pre-drilled .046 plate. Get a numbered drill bit set ($20 from harbor freight), and slowly increase your drill bit size until you are satisfied. Repeat with the other 1 or 2 holes.
Rayrevolver
08-22-15, 08:29
Another option from POF that I assume is new to the market? For. 750 gas blocks i still like the Govnah, baby Govnah, or BRT inserts. Or find a pinned
Noveske Switchblock.
http://www.rainierarms.com/pof-dictator-adjustable-gas-block-223-mid-length?utm_source=New%2FSale%20Email%208-21&utm_medium=Email&utm_campaign=New%20Email%208-21
cst - please post failures, I am interested in hearing about them.
Do the POF and Noveske vent gas like most other adjustable gas blocks?
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Are you asking if the adjustable gas blocks leak? Or are you asking if they use venting to reduce the amount of gas that goes to the BCG?
The SLR I'm using leaks, but it does not use venting to control gas flow. The SLR (and a far as I know the others as well) restrict gas flow
Yes, I guess leaks is the more accurate way to say it.
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Am quite certain my SLR Sentry 7 clamp on does not leak, at least around its contact with barrel, as I removed it and journal was completely clean, no trace of carbon. Now front end of gas tube did have some carbon deposits first inch or so, common in my limited experience. This makes sense, as clamping action allows gas block internal surface to pretty much mate to surface area of most of barrel journal. I know some folks dislike clamp on style, but as long as excessive torque on screws is avoided, they are not likely to shear. High temp moderate strength loctite (246) and witness marks are my insurance of gas block not moving.
This thread makes me less willing to try an agb, even slr. Could one get a suppressed sbr to run without too harsh of a recoil impulse/gas to the face by simply using an A5 w/ the "right" buffer, green sprinco and an LMT e-carrier? Let's also assume a surefire socom II is used, and the barrel is a 10.5" centurion arms lw chf bbl.
I mean before today's gas blocks, carriers and charging handles, was it a complete miserable experience to shoot suppressed?
BufordTJustice
09-03-15, 22:26
This thread makes me less willing to try an agb, even slr.
I mean before today's gas blocks, carriers and charging handles, was it a complete miserable experience to shoot suppressed?
Answer: Yes.
I know I'm reviving this thread but I have SLR, Superlative Arms, and Syrac Gen 2,... had my first Syrac lockup last weekend - destroyed it trying to free it up, other Syracs were very difficult to break free, the SLRs were cake, and the Superlative Arms is newer but still very easy to turn...
I neglect them all equally so take that with a grain of salt but I will move away from Syracs to only SLR/Superlative
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556BlackRifle
05-15-17, 09:16
I know I'm reviving this thread but I have SLR, Superlative Arms, and Syrac Gen 2,... had my first Syrac lockup last weekend - destroyed it trying to free it up, other Syracs were very difficult to break free, the SLRs were cake, and the Superlative Arms is newer but still very easy to turn...
I neglect them all equally so take that with a grain of salt but I will move away from Syracs to only SLR/Superlative
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Unless something has changed, Syrac is out of business.
I thought superlative engineered the syrac gas blocks. Now they've improved on them and make their own.
I think the BRT Micro Tune GB is the way to go.
Just my $0.02
I thought superlative engineered the syrac gas blocks. Now they've improved on them and make their own.
You're right, they owned the IP, and redesigned it into the Superlative
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