Why is there a perceived need for the type of guns that olddude objects to? Two reasons, the wording of your second amendment and the rather mystifying truth that it would appear that Americans just simply do not trust their Government (If the Army and National Guard units have automatic or semi-automatic weapons, then I too must have those types of weapons to allow me to defend myself).

Make it harder to buy and own a gun? - Impossible in a country that already has more "licenced/registered" guns than people (112.2 guns for every 100 people in the country). The number of unlicenced and unregistered firearms will be staggering and among those you will have all the "war souvenirs" dating back to WWI.