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Armalite Adjustable Gas Block Help

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Silver:
So, I installed some floating handguards and non-adjustable low profile gas blocks on my ARs and had mixed results.  The AR-15 survived and is firing well.  The AR-10 however has gone bolt action on me failing to feed any round (tried 5 different types -- surplus plinkers to match ammo) I put in it.

I researched the problem and one potential issue that may be the cause is that the S&W M&P10 supposedly has a smaller port on the gas tube than any similar AR-10.  FTF is not an uncommon problem with the rifle for some folks even if unmodified.

I had previous FTF problems before the mods but generous oiling and a solid cleaning seemed to fix it.  That didn't work this time around.

Buying into the theory that the port on the gas tube may be just too small, I've replaced the gas tube and paired it with a new adjustable gas block.

The Armalite adjustable gas block did not come with instructions and given the holes in the block, I'm not sure how it functions. 

Watching videos of other adjustable gas blocks it seems there is an additional hole and you simply adjust flow by tightening or loosening the screw. This one has two screws however and they intersect each other though it doesn't look like either one would fully seal off the chamber/opening of the other.

The question is, how do the two adjustment screws work in conjunction with each other? I can see the need for one and how tightening or loosening it could create the right pressures but not how the two would operate together.

Any thoughts?  Diagram attached.

Thanks in advance.

Dan W:
I am not familiar with that gas block, but I think (read wild guess) one screw is the gas adjuster and the other is probably a lock screw

JAK:
Based on other adjustable gas blocks I have used, the screw on the side should be the locking screw and the one in front the adjustment screw.

John K

shooter:
 you said FTF. fail to feed. do you mean the bolt isn't going back far enough to grab a new cartridge? sounds like not enough gas. a bigger tube should have helped, but if it didn't , I think that maybe the gas port in the barrel itself is to small. adjusting the gas down will not make a difference if you need more gas,
   You might have to inlarge the gas port.

Dan W:

--- Quote from: shooter on April 08, 2016, 04:15:17 PM ---   You might have to inlarge the gas port.
--- End quote ---
I agree...open up the gas port and then use the adjustable gas block to tune it in

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