Bravo Company often gets into the business of making AR15 parts or accessories after not being satisfied with what they can already buy to build their complete receivers and rifles. Their new Enhanced Lower Parts Kit is one of these products.
After having trouble with the quality of the parts kits they could buy to build their lowers and rifles, Bravo Company decided to start making them themselves. Like for all of their products, BCM deferred to the original Technical Data Package for the AR15 in determining not only the dimensions of the parts but also the materials used and the methods of manufacturing.
For more information, visit http://twangnbang.net/?p=277&preview=true.
Two great lower assembly videos to watch in addition to this one: https://www.youtube.com/watch?v=VBoh-o6iN24 from Mrgunsngear https://www.full30.com/video/d8db6633fb601a3ecb3cea916474d587 from Sootch00