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Posted: 8/6/2014 7:41:51 PM EDT
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My .308 started out life as just a bone stock Oracle. Since owning it i've installed a Rainier arms select 16" barrel with midlength gas system. I used a rifle buffer and tube and had cycling issues. The gun cycled fine with a suppressor but not so much without. Switch back to a 308 Carbine buffer and tube and still no reliable cycling. I bought a Syrac adjustable gas block and still cannot get this thing to cycle reliably to save my life.
I am at a loss. The bolt is well lubed and everythings tight like it should be. I have emailed Syrac to see if they had any recommendations on what to do. Rainier says that it's half the fun of owning a 308 (trying to make it run) To be honest its really starting to piss me off. For what I paid i feel like a little information would be helpful. Here is the rifles specs. Rainier Arms Select 16" midlength. Syrac adj gas block. Troy Alpha rail Geissele Super dynamic combat trigger Milspec buffer tube Troy battleax stock I am on the verge of just selling the gun or trading it for a Socom 16. Could the gasport be wrong? Should i open it up? Should i say fuck it and put the stock barrel on it?  " />
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What kind of malfunctions are you getting?
I dislike using AR15 length receiver extensions on .308 rifles, the AR10 carbine had it right with a slightly longer (~3/4") tube and stiffer spring. Armalite AR10 Carbine Tube or Vltor A5 tube (same thing) Armalite AR10 Carbine Spring Armalite AR10 Carbine Buffer (Exactly the same as H3) Another common issue is lack of spring tension on the extractor. I'd made my own replacement with some spring stock I'd found around the shop but you can also use things like the o-rings from AR15 bolt upgrade kits. Look for gas leakage around the gas block & gas tube. I'd probably lose the adjustable block but that's me. If nothing else works, put it back to the original configuration and start working back from there, one piece at a time. |
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Quoted:
What kind of malfunctions are you getting? I dislike using AR15 length receiver extensions on .308 rifles, the AR10 carbine had it right with a slightly longer (~3/4") tube and stiffer spring. Armalite AR10 Carbine Tube or Vltor A5 tube (same thing) Armalite AR10 Carbine Spring Armalite AR10 Carbine Buffer (Exactly the same as H3) Another common issue is lack of spring tension on the extractor. I'd made my own replacement with some spring stock I'd found around the shop but you can also use things like the o-rings from AR15 bolt upgrade kits. Look for gas leakage around the gas block & gas tube. I'd probably lose the adjustable block but that's me. If nothing else works, put it back to the original configuration and start working back from there, one piece at a time. No gas leakage. If i go back to standard carbine gassed factory barrel everything works correctly. Thats a 16 inch carbine gas with low pro non adj gas block. Instal midlength with low pro non adj gas block. Inconsistent ejection and it jams itself up. I've had people say under gassed AND over gassed. Shooting with suppressor works fine. Midlength with adjustable erratic ejections, double feeds everything. Have not shot suppressed with adjustable gas block. |
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I have the same barrel on my Iron Ridge Arms build. I built it with a JP Ent. low mass BCG, a JP Ent. adjustable gas block, for a buffer I used Slash's Heavy 5.5 oz carbine buffer and his carbine spring. It ends with a Sopmod stock. http://heavybuffers.com/ar10carbine.html I haven't encountered any issues with ejection or feeding, I've even tuned the gas down to get ejection of brass close enough to pick up from prone. |
| The fact that it will run with the can but not without means it's probably very undergassed. If you have confirmed that the gas block is properly aligned it's probably time to start slowly opening up the gas port. Can you measure the current gas port and see what size it is? |
| I would agree that it sounds like it is not getting enough gas, however before you do anything permanent like enlarging the gas port I recommend making sure there isn't any gas leakages. I would check the gas key on your bolt carrier as well as the gas block and tube to see if there is any gas escaping from either of those areas. If that isn't the happening you may want to look at your recoil system, maybe a different length buffer tube or different weight recoil spring. Just some other less expensive options to look at. |
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The fact that it will run with the can but not without means it's probably very undergassed. If you have confirmed that the gas block is properly aligned it's probably time to start slowly opening up the gas port. Can you measure the current gas port and see what size it is? I could measure it but it wont do me any good if i dont know what size its supposed to be. |
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I could measure it but it wont do me any good if i dont know what size its supposed to be. Quoted:
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The fact that it will run with the can but not without means it's probably very undergassed. If you have confirmed that the gas block is properly aligned it's probably time to start slowly opening up the gas port. Can you measure the current gas port and see what size it is? I could measure it but it wont do me any good if i dont know what size its supposed to be. Someone who is very knowledgeable (not me) about these may be able to confirm that it's too small. |
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What kind of buffer are you using? If you have a standard milspec 7" buffer tube you will need a shorter buffer, a 3.25" carbine buffer is too long. www.heavybuffers.com/ar10carbine |
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What kind of buffer are you using? If you have a standard milspec 7" buffer tube you will need a shorter buffer, a 3.25" carbine buffer is too long. www.heavybuffers.com/ar10carbine It is a standard 308 carbine buffer. Can you please explain why? I hold your opinion in high regards. |
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You are under gassed. Your gas block should not be touching the shoulder, but set back about the thickness of a couple of business cards. If it is up against the shoulder, then you are likely cutting off half of the gas supply.
I have also seen where either the gas block, barrel gas port, or gas tube has a partial blockage (I had one just the other day) from the factory, or occurred during installation. Personally, I remedy this by running a proper sized drill bit (by hand) into the ports, and run a long pipe cleaner through the gas tube. Otherwise, you have a serious gas leak as others have previously stated. |
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Quoted:
You are under gassed. Your gas block should not be touching the shoulder, but set back about the thickness of a couple of business cards. If it is up against the shoulder, then you are likely cutting off half of the gas supply. I have also seen where either the gas block, barrel gas port, or gas tube has a partial blockage (I had one just the other day) from the factory, or occurred during installation. Personally, I remedy this by running a proper sized drill bit (by hand) into the ports, and run a long pipe cleaner through the gas tube. Otherwise, you have a serious gas leak as others have previously stated. depends on the barrel, and gas block |
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Far from an expert here, but how many rounds through it? And none of my .308 ARs (SCAR-H doesn't count) ever ran fine for the first 100 rounds, and after that, I basically just dumped motor oil on them and did mag dumps. After a few hundred rounds, they really started to break in for me. This is why my SCAR is one of my favorite rifles to shoot suppressed. Out of the box, bone dry, it ran like a top. I would rather have two SCAR-17s than 3-4 AR-10s, I only wish I knew this a few years ago. (And I am not recommending running it bone dry for long, just that it will function in that manner) |
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Quoted: It is a standard 308 carbine buffer. Can you please explain why? I hold your opinion in high regards. Quoted: Quoted: What kind of buffer are you using? If you have a standard milspec 7" buffer tube you will need a shorter buffer, a 3.25" carbine buffer is too long. www.heavybuffers.com/ar10carbine It is a standard 308 carbine buffer. Can you please explain why? I hold your opinion in high regards. .308 rounds are longer that .223, so the bolt needs more travel room. Bolt travel is restricted when using a 3.25" buffer in a standard 7" carbine tube. The proper spring is important aslo. |
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I got a chance to sit down and really take a look at things. From what i can gather i had something stuck in the gas block. I opened the gas block all the way up and tried it. It cycled then systematically closing it after each shot i was able to find a sweet spot. I get good ejection at around the 4 oclock position. When shooting suppressed it throws brass to the 2-3 oclock position. I can live with this.
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I fucking, da-da-damn it to all hell, RE-FUCKING-PEAT.
Straight or mil-spec gas tube? SYRAC ORDNANCE is SO FUCKED UP at this time. My two (2) 0.936" Series II clamp-on gas blocks take straight tubes. I now have a bent mil-spec rifle and mil-spec carbine length gas tube. WILSON COMBAT sent me straight gas tubes by UPS Ground and I received them in less than 24 hrs, Ground shipped as fast as NDA as a matter of fact. I had to call them since their site is also a tad behind the times. Syrac Ordnance also uses the equivalent of Chinese pot metal for their screws. They are so far from Grade 8 as to not being in the same universe. And the threads cut into the SS gas blocks look as if done by someone having a seizure. They forgot to drill the gas port on my second gas block so I lost another week on my upgrading. Yeah, I've got pics. 
Growth pains are one thing. Absolute shit for brains cluster-fucknest... da-da-amn. They do have the best design. |
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I fucking, da-da-damn it to all hell, RE-FUCKING-PEAT. Straight or mil-spec gas tube? SYRAC ORDNANCE is SO FUCKED UP at this time. My two (2) 0.936" Series II clamp-on gas blocks take straight tubes. I now have a bent mil-spec rifle and mil-spec carbine length gas tube. WILSON COMBAT sent me straight gas tubes by UPS Ground and I received them in less than 24 hrs, Ground shipped as fast as NDA as a matter of fact. I had to call them since their site is also a tad behind the times. Syrac Ordnance also uses the equivalent of Chinese pot metal for their screws. They are so far from Grade 8 as to not being in the same universe. And the threads cut into the SS gas blocks look as if done by someone having a seizure. They forgot to drill the gas port on my second gas block so I lost another week on my upgrading. Yeah, I've got pics.
Growth pains are one thing. Absolute shit for brains cluster-fucknest... da-da-amn. They do have the best design. Start buying SLR adjustable gas blocks. |
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