View Full Version : Syrac Ordnance gas block pinning
Does anyone know who could or would taper pin one of these blocks to my barrel ? Because of the hard melonite finish on it, places like Adco and Rainier Arms don't really want to mess with doing it.
http://2.bp.blogspot.com/-FBccIHTI0oY/T9eXAvfY6pI/AAAAAAAAC8o/3weRxkzTHJE/s1600/Imgp2742.jpg
Does anyone know who could or would taper pin one of these blocks to my barrel ? Because of the hard melonite finish on it, places like Adco and Rainier Arms don't really want to mess with doing it.
http://2.bp.blogspot.com/-FBccIHTI0oY/T9eXAvfY6pI/AAAAAAAAC8o/3weRxkzTHJE/s1600/Imgp2742.jpg
Why would you pin that? Will it be exposed? Or under a rail?
I installed mine about a week ago, and just drilled some shallow holes where the set screws go and loc-tited the screws in. Since mine is covered by a rail, I forsee no issues with it moving.
Why would you pin that? Will it be exposed? Or under a rail?
I installed mine about a week ago, and just drilled some shallow holes where the set screws go and loc-tited the screws in. Since mine is covered by a rail, I forsee no issues with it moving.
Because I simply prefer to have the gas blocks on my rifles pinned, even if they are under the rail.
Because I simply prefer to have the gas blocks on my rifles pinned, even if they are under the rail.
Well...good luck.
Why would you pin that? Will it be exposed? Or under a rail?
I installed mine about a week ago, and just drilled some shallow holes where the set screws go and loc-tited the screws in. Since mine is covered by a rail, I forsee no issues with it moving.
Look atchu and all the new toys. Interested to hear your thoughts on it!
BufordTJustice
12-06-12, 18:52
Damn. I'm in the same boat.
The only other option is to put some divots for the scews to sink into.
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Look atchu and all the new toys. Interested to hear your thoughts on it!
Haha your day will be here soon :D
It definitely works. You can close off the port completely and turn your AR into a single shot or open it up all the way and run with the GP size that your AR came with. I went from pretty harsh recoil (at least for 5.56) and really fast bolt speed with 1:00 ejection to a VERY light/smooth recoil and 3:00 ejection...I think I may be able to tune it down a tad more, but I still want the bolt to lock back reliably.
I don't know if you read Grant's thread about his tuned SBR, but he tuned the GP to run the bolt reliably, but not lock back, so I'd imagine that his shoots even softer than mine.
It's definitely a solid piece of equipment.
Damn. I'm in the same boat.
The only other option is to put some divots for the scews to sink into.
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This is what I did.
As long as your rail covers the GB, you should have no problem as long as you properly install it in the first place.
Pappabear went over this topic with White Oak.
They WON'T do the pinning. They told him.. "why do you want to mess up the barrel harmonics?"
Depends on the gun's purpose for me. I can see doing it both ways.
EzGoingKev
12-08-12, 07:49
Option 1 - find a place that can EDM the hole in the gas block you need.
Option 2 - contact Syrac Ordinance directly and see if you can buy one with a hole directly from them. They should be able to machine the hole in prior to having the piece carburized.
Option 3 - blow off the pinning. You said the gas block is under the rail. Make sure the barrel is dimpled fairly deep, get longer set screws that stick out some. Drill them and safety wire them.
I will probably end up just having my machinist/ tool and die maker buddy who I trust and is fully competent set up the barrel and gas block on his Bridgeport mill. Then he can just lightly spot the drilling area on the gas block with a .125" inch carbide two flute end mill to break through the melonite finish and drill them. I will just have to buy a #2/0 reamer from Brownells or Midway for around $20 so he can fit the taper pin I got from Bravo Co. Having done a lot of machinist type work myself in the past, I can tell you it is not a difficult job *if *you have the right machine tools and experience. If you do not have the tools or experience (drilling and reaming) it can easily lead to a not so good outcome.
Pappabear went over this topic with White Oak.
They WON'T do the pinning. They told him.. "why do you want to mess up the barrel harmonics?"
Depends on the gun's purpose for me. I can see doing it both ways.
Pinning messes up the harmonics?
Do you have any more info on this?
Pinning messes up the harmonics?
Do you have any more info on this?
IMHO, anyway you attach a gas block or muzzle device to a barrel will mess up the harmonics of the barrel to some degree. It is just that some ways can mess it up more than others and affect accuracy more than others. Noveske currently uses a straight pin on the gas blocks on their stainless barrels, and they have built their reputation on accuracy. I believe whether one uses a gas block that is clamp on, has set screws or uses straight or tapered pins, as long as the attachment method keeps the barrel in a somewhat stress free state and does not deform the bore, the barrels accuracy should be pretty much equal using any of them.
EzGoingKev
12-08-12, 13:02
Knights used to just press the blocks on IIRC.
BufordTJustice
12-09-12, 00:34
Knights used to just press the blocks on IIRC.
Yep. They use a hydraulic press to seat the gas blocks unless they changed this recently.
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I used this jig (http://www.rainierarms.com/?page=shop/detail&product_id=1398) when I drilled my Syrac (Noveske barrel install). It was necessary to grind out the top portion a bit, because the Syrac is wider there than the jig accommodated, but otherwise it's very similar in profile to the Vltor the tool was designed for.
Incidentally, I don't know whether the finish has changed from when they were initially introduced, but I don't remember noticing any issues breaking through it.
Pinning messes up the harmonics?
Do you have any more info on this?
I don't... again... it's what WOA told Pappabear when he talked to them about a barrel he was buying.
Obviously there are some great shooting barrels with FSBs pinned to them so... :confused:
crazymoose
12-12-12, 01:22
I don't... again... it's what WOA told Pappabear when he talked to them about a barrel he was buying.
Obviously there are some great shooting barrels with FSBs pinned to them so... :confused:
I have to preface my statement by saying that I have almost zero metallurigcal expertise. If any experts in the area read this, I hope they'll correct me if I'm incorrect.
That caveat out of the way, it's my crude understanding that machining steel stresses the metal, and heat treatments relieve this stress. Thus, any machining done post-heat treatment (such as milling holes through the barrel and then reaming them) is going to permanently stress the material. Pounding oversized taper pins into those holes can't help things out, either, and I have to wonder if taper pin installation might even minutely deform the bore.
As you point out, plenty of taper-pinned barrels shoot pretty damned well, so the effect is apparently not large. Still, the fact that there are very good companies who avoid it with measures like pressed on or clamped gas blocks, or those FSB's which attach via four set screws and milled flats, I have to think there is some accuracy loss from pinning.
The amount of material removed to install a taper pin is so small, that it's almost laughable. That you think it could deform the bore is simply over estimating the amount of force being applied and how much structure there is in the barrel - even a pencil profile with a .625 OD at the gas block isn't going to be kinked from a properly placed pin.
The amount of stress induced by a taper pin is so minimal, that it's not going to impact the accuracy of the barrel. But even if it did - there would only be a change if you looked at POA/POI before and then after the pins were installed. Since you're shooting it in the pinned condition, there's nothing changing from shot to shot, and as such there's no loss of accuracy or repeatability. If the pins were loose, then you might see a change as the inherent stress of the system would be degraded over time and the pins no longer would act as a static load within the system, but even that would be hard to measure at the target and without using sophisticated measuring equipment on the barrel.
Speaking of the system - the gas block adds a structural support to the barrel, especially if it's rigidly affixed like with pins. It's like adding a truss around the affected area.
Without doing engineering modeling (beyond my scope of abilities), it'd be hard to say what, if any impact was being imparted by any of the methods (screws impart forces as well). What it all boils down to in the end is that consistency is the highest priority for ultimate accuracy.
Yep. They use a hydraulic press to seat the gas blocks unless they changed this recently.
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They used to press fit the gas block & use two set screws. All new models are pinned with dual taper pins. They started pinning the gas blocks with the introduction of the 2012 lineup.
EzGoingKev
12-12-12, 18:17
I thought I had read somewhere they changed the installation method because their military users wanted something easier to service?
Kevin Boland and some other Knights' guys post here so maybe one of them could chime in.
As long as the block is reasonably snug... drill dimples for screw engagement, a liberal application of loctite 638 on the block w/ red on the screws, then stake the snot out of the screws.
I've found rocksett to work extremely well to retain gas block screws, yet still allow reasonable removal.
Also, has there been any problem with the Syrac's gas block adjustment screw or other internal components after they get carboned up with long term use ?
Also, has there been any problem with the Syrac's gas block adjustment screw or other internal components after they get carboned up with long term use ?
I've been wondering that myself. I'm thinking the gas would also erode the tip of the screw pretty quickly.
DreadPirateMoyer
04-30-13, 15:05
Resurrecting this thread from the dead for hopefully pertinent reasons. :)
1. Has anyone found a place willing to pin a Syrac block or gotten ahold of Jason at Syrac to discuss the possibility of getting a block with a pre-drilled pin hole?
2. Is there any problem with attaching the Syrac set-screw block on a barrel that has already had material removed for a previous pinning? I just ordered one of Grant's new DD 16" Middie uppers with nitrided barrels, but the DD gas block is pinned. If I can't find some way to pin the Syrac on the barrel, I'll have to settle for simply set screwing it on. I don't know enough about the technical side of ARs to know if that's a problem or not.
Thanks everyone. :)
I'm running a few block with just the set screw... Including my syrac now. Dimple the barrel and rockset the screws and it seems fine. :confused:
DreadPirateMoyer
04-30-13, 15:18
Works for me! And it will be underneath a rail anyway, which seems to make the pinning unnecessary from what I gathered in this thread.
I just didn't know if there was a problem using set screws to hold a block onto a barrel that was previously pinned. I'm out of my league here when it comes to gas blocks.
I just recently did a Syrac gas block install and had my gunsmith pin it. Zero issues with pinning it.
The one thing I am concerned with is that I can't seem to close the gas port enough. I have a email out to Syrac to see if there is a fix.
DreadPirateMoyer
04-30-13, 22:31
That's awesome news on the pinning. Hopefully whoever works on my upper will be willing to do the same.
With regards to the gas block not closing as much as needed, how old is it? Syrac said that the first production blocks (mostly purchased before December, though some still lingered in the market into 2013) wouldn't completely shut off the gas if closed all the way, and the newer blocks supposedly have been fixed and should close as far as necessary to shut off all gas.
I'm not sure when the block was produced as I bought it from Brownells.
I also installed a Syrac and wanted to dimple my barrel. I made a drill guide out of a roll pin. I threaded it and installed it into the block. I left the other screw in so nothing could shift. I used a nylon spacer on my drill bit for depth control. Rocksett just for insurance. Ignore the Noveske block....it's the block I replaced.
http://paddle007.smugmug.com/photos/i-Wddzz6B/0/L/i-Wddzz6B-L.jpg (http://paddle007.smugmug.com/Other/Camera-Awesome-Photos/21717568_86sHn8#!i=2487910504&k=Wddzz6B&lb=1&s=A)
bleaman225
05-01-13, 18:29
I also installed a Syrac and wanted to dimple my barrel. I made a drill guide out of a roll pin. I threaded it and installed it into the block. I left the other screw in so nothing could shift. I used a nylon spacer on my drill bit for depth control. Rocksett just for insurance. Ignore the Noveske block....It used for a prop.
That's a good, simple idea with the roll pin. I like it.
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