hp: 29 attck: 31 def: 31 spec attck: 28 spec def: 30 speed: 27
Astronautical and sumwun are right they are good Ivs but if you plan to use Gyarados for Competitive, I'd go for 31 Ivs in all stats except Special Attack. If it's not Jolly or Adamant then you should get a new Gyarados with the right Nature or if its the right nature if your playing Sun and Moon get some bottle caps and get Gyarados to Level 100 and Hyper Train it. Here's a possible Set for Competitive.
Gyarados @ Life Orb Ability: Intimidate Evs: 252 Atk / 252 Spe / 4 Def Adamant Nature (+Atk, -SpA)
- Ice Fang - Waterfall - Earthquake - Dragon Dance
Hope this helps :)