If like to point out first that a ghost can be killed by a single bullet. It's written in the lore of destiny. Second, the guardians magic would never break Spartan armor or its over shield as a Spartans armor and over shield combined are able to withstand any amount of heat a ballistic force going towards them. Their armor allows them to survive nuclear blasts that destroy super planets. Third, the spartans augmentations give so many advantages as they can run over 60mph, have unbreakable ceramic bones, lined lungs allowing them to breath anything that's not oxygen for over an hour, enhanced 5 senses, thruster systems, highly advanced heads up display that could target an enemy from over 3 miles, their bud system allows to fire without missing shots, enhanced strength, extremely maneuverable in the armor despite it weighing over 1000 pounds (imagine being just simply ran into). Fourth, the Spartans completely outnumber all guardians in forces. Fifth, a Spartan Fireteam consists of 6 while a guardians is 3.