This is where I stand on this topic.
I often see gun advocates claim that the average citizen should have easy access to assault rifles because U.S. soldiers carry them and the 2A means that citizens need to be able to defend themselves against the government if the government declares martial law and wants to oppress/rule the people. In other words, citizens need these high power weapons to prevent them from being forced to bring a knife to a gun fight.
It is a flawed argument. Even with high powered rifles, citizens are already bringing a knife to a gun fight. If a military force wants to take over, they are going to have far more firepower than a group of armed citizens. Grenades, tanks, gas, drones, etc.
This is why I think assault rifles is an arbitrary line that can be adjusted. The only logical argument that can be made is that allowing citizens to have them with minimal restrictions is that it makes it harder for the government forces to take over. I'll buy that. But, it is not the same as "we need these weapons to keep the government from going too far".
I'm opposed to repeal of the 2A. I'm opposed to mandatory gun buy backs. But, I don't think the status quo is working, and I think it is possible to make some changes to current gun laws without violating the 2A. Not everyone would be happy with the changes, but they will be much more upset when they lose a loved one to a mass shooter, simply because he/she was in the wrong place at the wrong time.