——The missile flies more than twice the speed of a sniper’s bullet and is almost impossible to stop.——
A snipers bullet?
I will admit not to be a expert...but a sniper bullet is normally a FMJ and that’s the biggest difference between a civilian round...
What does speed of the bullet have to do with it?
That's a colorful comparison for those in the reading audience who think that "4,600 mph" isn't as fast as, say, a 747.
Regards,