Syrac gas block problem

[bigkyle72]

So its my 1st trip out to the range with the the gas block, and I followed all the instructions (started out with it all the way closed, put more gas in a 1/4 turn at a time) I got to the point where it would eject the round but would not grab the next round in the magazine and wont lock back when magazine is empty. I have it all the way out almost and still same thing.

My set up:

full auto BCG

carbine length gas system

16" barrel

stock buffer spring and buffer

PS-also have a taccom Ultra light weight buffer system, threw that in there and same thing. I started out with the stock buffer spring and buffer because I wanted to make sure to change only one variable at a time if something was wrong. Neither of them are working so I threw in my non adjustable block and it runs fine.

[APL-G35]

Sounds like a misaligned gas block

[bigkyle72]

The gas block Misaligned, do you mean the actual block is not lined up right or where the tube goes into the BCG?

[rboyes]

The gas block is misaligned with the gas port on the barrel most likely. Ensure that there is some space between the shoulder on the barrel and the gas block and you should be good to go, ie the Syrac is not supposed to be flush with the shoulder.

[MarkCO]

The gas block Misaligned, do you mean the actual block is not lined up right or where the tube goes into the BCG?

One or both could be an issue. Snaking a gas tube through the barrel nut, I have seen folks get the tube misaligned with the gas key and create enough leakage to affect cycling.

[openclassterror]

The nominal OD on the end of the gas tube is 0.180 inches. Nominal ID on the gas key hole is 0.182. Assuming both are in spec, there shouldn't be enough room to leak significantly more gas, even if it is touching on one side. The culprit is usually DRAG. If the gas tube is off center going through the delta ring assembly, it often rubs on one side of the bore in the gas key in the carrier. If carried to the extreme, it can push the carrier key sideways far enough to rub on the side of the channel in the upper receiver. It isn't a huge amount of friction, but enough to slow the unlocking at its most critical point. However, due to the recurrence of this same theme on the Syrac gas blocks, I would start looking at that end of the gas system first.

[bigkyle72]

Thanks openclassterror! That was it! Got it all dialed in. Is it just me or does it seem like it doesn't help that much? It could be just me. I'll be shooting it this Saturday in a match so I'll see what it feels like when I step on the gas with it and run it hard.

[openclassterror]

You will get the most help from the adjustable gas blocks if you have made system mods that require less gas to run. For instance, with a super light carrier/ buffer assembly, it takes less gas to cycle. So, you can throttle the gas back to reduce the impulse of the buffer bottoming out in the buffer tube to keep the rifle tracking better between shots. Keep in mind that in a fixed gas block, the hole size in the barrel is what limits gas flow. With a Syrac installed, the hole size in the barrel has not changed so at wide open, the gun gets no more gas than with the old gas block. It needed about that much gas before, so why would that change? You can only turn it down a bunch if it was way overgassed to start, or you have changed something so it NEEDS less gas.

[waktasz]

yep. Ditch the huge bolt carrier.

[bigkyle72]

yep. Ditch the huge bolt carrier.

Ok so I have a stag left handed AR and I was wondering if I could take the bolt out of my BCG and use the LH bolt in a JP low mass BCG.

[chase214]

i had one on my rifle worked great then one day the bolt wouldnt lock to the rear on the last round i went to adjust it and the plunger was stuck and once i got it to work the the screw wouldnt turn to adjust anyone had this prob.

[StealthyBlagga]

... Ensure that there is some space between the shoulder on the barrel and the gas block and you should be good to go, ie the Syrac is not supposed to be flush with the shoulder.

Can anyone tell me how wide this gap between the Syrac gas block and the barrel shoulder should be?

ETA: I pulled a GI handguard retainer out of the parts bin - it is ~0.03" thick. I'll use this spacing and see how it goes.

Edited January 9, 2014 by StealthyBlagga

[StealthyBlagga]

Moving the gas block away from the barrel shoulder about 0.03" is giving me much more robust cycling - the bolt locks back on an empty mag every time now. I wish Syrac would put this nugget of wisdom on their instruction sheet, or even better include a spacer.

[MarkCO]

Moving the gas block away from the barrel shoulder about 0.03" is giving me much more robust cycling - the bolt locks back on an empty mag every time now. I wish Syrac would put this nugget of wisdom on their instruction sheet, or even better include a spacer.

Almost every gas block on the market is sized for the mil-spec handguards, so a 0.025 to 0.030" gap is common when doing a FFT build.

[StealthyBlagga]

Moving the gas block away from the barrel shoulder about 0.03" is giving me much more robust cycling - the bolt locks back on an empty mag every time now. I wish Syrac would put this nugget of wisdom on their instruction sheet, or even better include a spacer.

Almost every gas block on the market is sized for the mil-spec handguards, so a 0.025 to 0.030" gap is common when doing a FFT build.

Does anyone sell a spacer plate? It would seem like a useful product if so many gas blocks have this issue, but I don't recall ever seeing one.

Edited January 9, 2014 by StealthyBlagga

[openclassterror]

That is interesting. Low profile gas blocks from Noveske, Sadlak, Troy, V7, and VLTOR that I have measured all have the port properly positioned for use without the stamped plate. Pretty much most of them that say they fit under a free-float handguard seem to account for the plate being missing.

[MarkCO]

Moving the gas block away from the barrel shoulder about 0.03" is giving me much more robust cycling - the bolt locks back on an empty mag every time now. I wish Syrac would put this nugget of wisdom on their instruction sheet, or even better include a spacer.

Almost every gas block on the market is sized for the mil-spec handguards, so a 0.025 to 0.030" gap is common when doing a FFT build.

Does anyone sell a spacer plate? It would seem like a useful product if so many gas blocks have this issue, but I don't recall ever seeing one.

Never seen a spacer plate. We designed our gas block to mate to the shoulder because so many are mil-spec.

[Doug H.]

To measure the offset I use a small piece of a Juicy Fruit gum box for 3 reasons. It seems to be the correct size, it saves me digging around for my feeler gauges and I always like to chew Juicy Fruit when I build a gun. Scott has a new barrel waiting for me, time to break out the Juicy Fruit!

Doug

Edited January 9, 2014 by Doug H.

[Pat Miles]

Moving the gas block away from the barrel shoulder about 0.03" is giving me much more robust cycling - the bolt locks back on an empty mag every time now. I wish Syrac would put this nugget of wisdom on their instruction sheet, or even better include a spacer.

Almost every gas block on the market is sized for the mil-spec handguards, so a 0.025 to 0.030" gap is common when doing a FFT build.

Does anyone sell a spacer plate? It would seem like a useful product if so many gas blocks have this issue, but I don't recall ever seeing one.

Just use the appropriate thickness feeler gauge between the shoulder and the back of the gas block. Easy peasy.

Pat

[Bentsight]

i had one on my rifle worked great then one day the bolt wouldnt lock to the rear on the last round i went to adjust it and the plunger was stuck and once i got it to work the the screw wouldnt turn to adjust anyone had this prob.

I've got one of the Gen I blocks and recently was building some new loads so I needed to change the setting. I have fired 500~ rounds since the last time I attempted to adjust the flow and found the thing locked up tight at this point. I have soaked it in brake cleaner, Kroil and put it through multiple sessions in my sonic cleaner with no luck. I have attempted to contact them by phone and EM but have received no replies or I wouldn't be posting my problems here. Has anyone else encountered this and if so how did you correct it?

[bigkyle72]

i had one on my rifle worked great then one day the bolt wouldnt lock to the rear on the last round i went to adjust it and the plunger was stuck and once i got it to work the the screw wouldnt turn to adjust anyone had this prob.

I've got one of the Gen I blocks and recently was building some new loads so I needed to change the setting. I have fired 500~ rounds since the last time I attempted to adjust the flow and found the thing locked up tight at this point. I have soaked it in brake cleaner, Kroil and put it through multiple sessions in my sonic cleaner with no luck. I have attempted to contact them by phone and EM but have received no replies or I wouldn't be posting my problems here. Has anyone else encountered this and if so how did you correct it?

How long has it been sence you emailed them? They got right back to me and sent me out a pre-paid box and replaced it. Maybe check your junk mail?

[waktasz]

I gave the end of the plunger a tap with a hammer and it freed right up

[mpom]

Moving the gas block away from the barrel shoulder about 0.03" is giving me much more robust cycling - the bolt locks back on an empty mag every time now. I wish Syrac would put this nugget of wisdom on their instruction sheet, or even better include a spacer.

Almost every gas block on the market is sized for the mil-spec handguards, so a 0.025 to 0.030" gap is common when doing a FFT build.

Does anyone sell a spacer plate? It would seem like a useful product if so many gas blocks have this issue, but I don't recall ever seeing one.

Maybe its my OCD, but when replacing a gas block, I simply use a caliper to measure edge of boss/shoulder to center of gas port, then measure edge of gas block to center of gas port, which is usually less and then use the correct feeler gauge to position the gas block. I also scribe a pencil line along center of gas port on top of barrel to aid with aligning the gas block side to side.

Have not installed an adjustable one yet, but lo pro Noveske and clamp on VLTOR do require around .028 space between shoulder and edge of gas block for proper alignment.

[Mark Gale]

Have not installed an adjustable one yet, but lo pro Noveske and clamp on VLTOR do require around .028 space between shoulder and edge of gas block for proper alignment.

Not true... If the center of the gas port is a standard 0.295 of an inch from the shoulder on the barrel, it's not necessary to space a Noveske or Vltor gas block. This is not the case with a JP or DA7 which both have much smaller plenums. I don't have a Syrac to take measurements off of for comparison.

Even with a rifle sized gas port (0.0935), due to the size of the plenum in a Noveske/Vltor gas block, there would be no gas port occlusion until its diameter reached about 0.102 of an inch.

You can see in the drawing below that it wouldn't hurt to offset the gas block by 0.030 of an inch. It's just not necessary.

https://www.dropbox.com/s/7vh9hl1f5c3y0ic/Gas%20Port%20Plenum%20Comp.jpg

Edited March 30, 2014 by Mark Gale

[mpom]

Can now see its not necessary to offset the gas blocks, however Noveske did offset the block when they assembled my upper, so thought its prudent to follow their example. No harm and keeps ports concentric.