I'm not sure if this has been mentioned yet but the AR-15 and 10 are not assault rifles, they're semi automatic rifles. Granted, with a tax stamp ($200), knowledge on how to modify them, and the parts ($10,000 to $20,000+) you could potentially make them fully automatic, but the same could be said for any semi automatic rifle on the list. Also, have you considered adding the M14 or the M1A civilian counterpart?