Fantastic bcg if you have an adjustable gas block - Walker Defense Research Research Titanium Bolt Carrier Group (BCG)

This BCG is light weight. If you want to take full advantage of that you need to combine it with a gas system that can reduce the amount of gas introduced into the system. Otherwise, this will cycle too fast. As long as you know what you are getting into, this is a fantastic BCG. But a BCG doesn't operate in a vacuum and has to be paired with less gas to slow the cycling.