AR trouble

[JosephR]

Someone is suggesting it is canted and therefore blocking the port. that would require a lot of work to fix and no way to know for sure before beginning.

I'm saying the tube is leaking. Either too large of a hole (worn?) in FSB or worn tube...

Tube shouldn't wear and neither should FSB.

Clean the tube and FSB very well with brake cleaner. It will not hurt the finish. Fire 50 rounds and see if more soot develops.

 

[barber613]

Got out for some trigger time today with great results. First I want to thank everyone who tried to help me solve this issue. After trying all the things except removing the sight block, the gun is now running perfectly. The last thing that I did was to get brake cleaner and spray out gas tube and front sight block out. After seeing the gun disassembled along with my colt ar disassembled I now come to the conclusion that the gas was not leaking, but blocked in the front sight. While the tube in the problem ar was dirty on the end, it was not nearly as dirty as the tube in the working colt. Long story short the gun functions flawlessly, and now not sure I want to sell it. After all if one is good two must to be, well you know the rest. Thanks again to all.

 

[JosephR]

I am surprised. Its almost impossible to clog a gas tube. The pressures are too high. Either way, glad it works! The saying is "two is one, one is none" if you consider the chances of something failing.

 

[techres]

The last thing that I did was to get brake cleaner and spray out gas tube and front sight block out.

I give all credit to Andrew over at MCSports for that trick. Worked for me too!