
What happens if you miss?
Or more than 1 assailant?
Something tells me this was not well thought out. 
maybe more thought than you think.
the proposition certainly would put one at a tremendous disadvantage against multiple enemies or an enemy with an illegal semi- or fully automatic weapon.
however really take into account the idea that no matter where you draw the legal line, the law abiding citizens are always at a tremendous disadvantage
to those individuals who break the law.
for me, when i take that into account, i first consider the need for the freedom to arm oneself. it is essential to liberty i think, being able to defend oneself. and i realize that firearms are probably an integral part of that ability to defend oneself. especially if the government is going to have them. but i do not think that the citizens should be able to keep all the same kinds of firearms that the government should be able to keep. and i think i draw the line at single-shot firearms because the ability to shoot a single bullet is probably the most significant benchmark a person can meet in terms of physical defense. they are now almost assured of success if they ever need to kill anyone. no government official is safe.
idealistically i am an anarchist but i find it difficult to see the argument for liberalization of the laws concerning weapons. i consider it the top priority of the government, as keeping dangerous weapons out of the hands out of those who would use them for harm is the single most powerful tool in protecting national security.
(as for what if you miss your shot and what if you are confronted by multiple assailants.. well, sorry joe, looks like the forces against you trumped the forces with you.. government cant pretend to be able to stop that from ever happening)