"Plus your side keep telling me there is no deadliness difference between
a handgun and a semi-auto rifle, so what can you do with one that you can't
with a handgun?"
Minor differences at SHORT RANGE. At long range, it's a different story.
There is a reason Charles Whitman chose a rifle vs a pistol for his event.
For the younger folks who just said " Charles Who ? ", this link is for you: A motivated Marine and his rifle
In reality, in close quarters a rifle is actually a poor choice due to its
maneuverability issues in tight spaces, over-penetration hazards and the
difficulty in concealing said weapon.
"in a hypothetical situation where National Guard is going door to door
rounding up people to put them into concentration camps"
Didja know, during a recent high profile hurricane in Louisiana, Law
Enforcement ( local and Federal ) as well as the National Guard were going
from house to house rounding up all firearms ( illegally ) from all the
citizens because someone ( illegally, but in a position of power ) decided
that only Law Enforcement should be armed at that point. :|
To preempt those who want citations, this link is for you: Scroll down to the Confiscation of Civilian Firearms section
Oh and for everyone who thinks the might of the US Military cannot possibly
be defeated / thwarted by small groups of individuals armed with basic weaponry
and home made devices, I merely need point you to the following conflicts: