Sure can.
Nope.
Depends on who does it.
it is if it isnt free.
Get an AK instead.
The SKS is designed to be fired from a fixed 10 round fixed magazine fed by clips. It works fastest that way and is the most reliable. If you want/need more than 10 at a time, get an AK.
AKs are just too expensive right now, maybe in another 10 months or so I will be able to get one.