Originally Posted By: Stirling XDI just dealt with this same thing tonight. I swapped a barrel. The first few shots cycled fine but then I started getting failures to eject. The gas block felt a little loose at the range but at home it felt tight again. I took everything apart and put it back together. I tightened the set screws to 30 inch-pounds. Then I heated up the block with a heat gun. I got about another 20 degrees of turn on the set screws.
If your rifle is operating properly, it may not be worth worrying about.
You may also want to Loc-Tite the set screws for your block. I would not normally recommend Loc-Tite, but I have found that depending on the material that the block is made from and the thickness of the material that you may have a heat/cooling cycle issue with the block. Normally the block and barrels heat and cool at different rates and this can cause the gas block set screws to loosen up. Especially if you have a dimpled barrel where there is a pocket drilled into the barrel for the set screw. I have found that with dimpled barrels they tend to loosen up while non-dimpled barrels tend to stay tight. The non-dimpled barrels allow the gas block to maintain it's tension against the barrel while dimpled barrels allow the block to relax.
Yes, normally there is a bit of gas/carbon that vents around just about every gas block and gas tube. Normally the carbon will build up and seal itself off so that the leak does not continue nor increase. So if you are not experiencing malfunctions and the gas leak is not increasing, I would leave it alone.
