You have obviously done your research.
Paranoid leftist are not excluded from buying firearms.
Unless they have been adjudicated mentally defective,
Your could spend a lot more, or, you could spend a lot less.
Semi auto sporting rifles with detachable magazines have been around
for more than 100 years. Adding a bit of black plastic to make them lighter
has not increased their level of lethality.
"Congress have no power to disarm the people. Their swords and EVERY other terrible implement
of the soldier, are the birthright of an American. The unlimited power of the sword is not in the
Federal or State governments, but, where I trust in God it will ever remain, in the hands of the people."
Tench Coxe(Continental Congress 1788)