Colt cycling issues

[bobbyfairbanks]

So I have a Colt Ar-15. I replaced the front sight Block (FSB) With a Flip up Front sight gas block. I am 100 percent sure That I did this right. Now I am having cycling issues. The primary issue is failure to extract. So I am guessing that I did not install gasblock correctly. I am looking for advice on how to fix the problem and where to start trouble shooting at.

[Circuits]

To help you diagnose, we'll need a complete description of the firing cycle.

For instance, by "failure to extract" do you mean that the bolt/carrier cycles, but leaves the empty stuck in the chamber, or that the bolt/carrier fails to extract the round or cycle?

When/if the rifle does cycle, what's the ejection pattern like, and the condition of the brass, etc?

As complete and accurate a description of the problem as you can give will save a lot of (perhaps unnecessary) back and forth Q&A, and speed things up in myself and the other board members assisting you.

[bobbyfairbanks]

The BCG I do not believe is moving full cycle. I have to charge the weapon eveytime. If it did happen to cycle the brass is in good shape. Still reloadable. Sometimes it feels a little suglish. That is why I think the BCG is not moving through the complete cycle and leaving brass in the chanber

[NukeRJ]

Did your rifle function flawlessly before the modification? If yes then take the fsb off. Measure the distance from the shoulder of the barrel at the rear of the gas block area to the center of the gas port.
Now measure the distance from the rear of the fsb to the center of it's gas port. Subtract second from first. This is the distance that the gap between the shoulder and rear of fsb should be. Usually in 10 thousandths.

Also ensure the port is clear of obstructions on both sides and check the gas tube to port alignment as well. Sometimes things just don't line up.

[bobbyfairbanks]

I will pull FSB tonight and check for obstructions as well as measure.

[bobbyfairbanks]

I got a different gas block. It seems the YHM one that I put on was leeking alot of gas. I had to knock it off with a rubber mallet. The outside of my barrel had a lot of carbon residue on it. I put on a GGG FSB and it now functions the way a Colt should. Perfectly. thanks for the commets it got my hamster running.