Deidara wins flys as high as he can gets his bombs ready gg for gai same can be said for 7th gates gai

That's why I said Gai closes the distance & then blitz him.Deidara reacted to Hebi Sasuke's shunshin from a much shorter distance. This is 50m so I atleast no he won't get blitzed.
Deidara gets blitzed. It's only 50m the op doesn't state Deidara starts in the air let alone on his bird so not only will he have to try and make his bird big enough so he can fly on it he'll have to get a respectable distance which he isn't going to be able to accomplish in the time he gets wrecked. Gai quickly goes 6th Gate and close the distance. Then he proceeds to use this Huge version of Hirudora[You must be registered for see links]
Need 7G for Hirudora
Anyways if Gai didn't start immediately in 6th gate Deidara most definitely wins, if he does I still think its a long shot but he has a chance to blitz.
Asa Kujaku on this calibur[You must be registered for see links] gets the job done as well.
That range is clearly not 50 meters, and it can be avoided in the air if he's not using it right next to him.