Crash Magic my man , not only that , he is so physically strong it is like he is the 3rd raikage in sage mode
Makarov has more powerful magic , but fairy tail does involve punch ups too , so gildarts with one hit to the face would win , and gildarts can probably use fairy law to counter fairy law , and with more magic power and a stronger, younger body his is probably gonna annihilate Makarov's fairy law
that was BEFORE gajeel became the iron-shadow dragon slayer , they are now equal again , actually... Gajeel>Natsu because he can become a shadow and therefore unharmed by fire or lightning