So I am 18 and I'm looking to start a lr-308 build (dpms ar-10). I understand that I cannot own an ar-15 lower because they are regulated, but I have recently spoken to MSP Firearms Unit that it is legal for me to own an ar-10 lower because they are not regulated and I would not have to fill out a 77r form. Any input on this? Is this true? And anyone use either the aero m5 set or the v Seven harbinger set?