@Alpha081106
if there is magic that can instakill someone why can't there be magic that protects you from bullets?
By that logic, there can be anti-magic magic that negates magic and renders an instakill spell worthless. And if anti-magic magic exists, just use that and then shoot the person.
The fact is, magic is a crutch in many fantasy worlds and magic would rarely fair very well against modern weaponry and tactics if the person utilizing them had a brain. Outside of the few things science can not accomplish (healing instantly, invisibility, ect.) and, I dunno, ambush tactics which could probably be done better with a machine gun and M18 claymores anyways...
Let's not even get into how magic usually requires someone trains and learns it for years upon years before being proficient in it whereas you can turn even an amateur into a competent shooter within a few months with firearms.