I hope your "brother" registered the machine gun he manufactured. If not he is in for bad ju-ju. I do not think "Sons of Guns" is a good example of true collectors and marksmen. Either there is quite a bit behind the scenes paperwork on some of those firearms, or they are outside the laws. I agree about the acts of 1936 and 1986 being bad law, but they are the law. IMHO the NRA does not have the stones to go after 1986. I am a life member, and I ask them this all the time. The 1986 act basically made it almost impossible to own any decent full auto firearms for less than $10,000. Sure you can get a MAC-10 type, some low end UZI's M-2 Carbine, M-50 Reislings, and suce under than mark, but if you want a decent Thompson, M3 Grease Gun, MP-40, those start at about $10,000 for transferable examples. If you bought in the 70's when there was a bit of a glut, you are sitting on a mint today.
For me the shooting is fun, but it is the history that makes me think. Why did Custer lose a Little Big Horn? In part because his men had to dismount to use their Springfield breech loading trap door carbines. Pick one up and see how hard they are to load. On the other hand they are fairly accurate and had hitting 45-70 gov't. When I pick up a gun, who held it before me? Was it on Omaha Beach, Tarawa, Inchon, Da Nang? That goves me awe.