Not sure if this is a Second Amendment post, a Firearms post or a freedom and liberty post. Either way, Post your links to self made weapons here. Knowledge wants to be free! http://thehomegunsmith.com/
If you decide to build an RPD or a Mk 19 from a demilled Parts Kit, there are some ATF regs you should be aware of. http://hellboxarmory.com/Common Questions.htm
If the time comes that I have to build one of these guns, the last thing I would be worried about is the BATF and their regs.