Kuei,
This post *almost* qualifies for posting in this forum on a few levels, but is generally not the intent of the forum itself.
I'm going to let it stand as it is vaguely related to gunsmithing.
As a moderator on AR15.com (and others), I and you both know that there are some serious legal issues attached to any endevour in building such a rifle.
I think we would also agree that most Class II holders, and others who could legally build such an item in the US would likely not be getting their plans from the internet.
I also believe in freedom of information, and so I will not delete this post based on that belief.
However, there is a good chance that this type of posting may not sit well with the site owner, especially compared with it's relatively low conformity to the intent of the forum....being more related to improving a machinist's gunsmithing skills from a machinist's point of view than the point of view of someone wishing to own such a weapon.
Gentleman to Gentleman, and as a person who has fired the FA M16 personally ,I am asking you to please consider refraining from such posts in the future on this particular site out of consideration for the site owner, and from the realisation that this is beyond the scope of this site.
Regards
Sean