I have a 16 inch barrel upper that has gas tube is leaking carbon at the front site and cause sometimes some failure to feed. What can be done?

is the gas block leaking where it connects to the barrel?? or is it leaking around the tube?? hard to tell without pics. might be as simple as a new roll pin or mis sized tube worn tube or wrong sized block or loose gas block.

good close up pics might help

Ok I don't see much from the last Range Trip. This time It would have a few failure to cycle the hammer back. Then ran fine but would not lock the bolt back on empty mag.

Are you running suppressed?? that happens a lot with suppressors in regards to blowby.

If you have a bad lever that is a huge cause of fail to lock back

Gas tube prolly is partially plugged may need a cleaning or replacement

Gas leak will cause all the problems cited. As JonM stated might be simple as repositioning the gas block or changing the tube but impossible to diagnose remotely. Anything appear loose, is sight post canted to left or right, is carbon on barrel or on gas block near pin or tube opening?

This is a new upper with a 16 inch barrel , the fowling residue that I found was on the stainless steel tube. No suppression just A2 bird cage. I will take off the Magpul BAD lever next time I fire it.

Is it because of the lever itself (weight or interference with part of the lower) or from the shooters trigger finger hitting it?

Per bravo company tech rep is it adds just enough mass and resistance on some guns to the bolt catch to delay it rising fast enough to catch the bolt

The bad lever isnt the cause of the gas blowby but its prolly the cause of the fail to lock open

The cheap method is to simply replace the gas tube. If you still get the blow by, the gas block (FSB) needs to be replaced. If it is new, I would contact the manufacturer.

Do you think it could start to seal it self up? The more powder down the pipe. The reason I ask is that now it's just doing it on the first mag then runs fine.