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.
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.
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?
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).
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.
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.
Really? The set screw in my Sentry 9 is clearly an #8-32.
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”
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.
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.
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.
It’s ok. Unfortunately the nature of the Internet is that people would rather argue than actually do anything helpful.
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.
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.
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 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.