Great team dude, you're definitely right about your dual RP sweepers doing work on offensive teams!
So for your Gyarados
weakness the simplest change I see is flipping Magnezone to a Choice Scarf Magneton
. The set I suggest is:
@ Choice Scarf
Trait: Magnet Pull
EVs: 252 Spd / 252 SAtk / 4 Def
- Volt Switch
- Thunderbolt / Thunder
- Flash Cannon
- Hidden Power [Fire]
Magneton provides a solid check to DD Gyarados, as it out speeds and OHKOs easily with its Electric-type attacks. This also provides a potent check to Tornadus-T
who I can see doing some work on your team as nothing resists it's moves while also out speeding on your current team. Magneton again can come in on its Hurricanes and threaten it out. Be aware though that this change will make it harder for you to reliably trap and kill things such as Ferrothorn in the rain. I believe though that with our current super offensive metagame its more pertinent to have offensive checks than ways around defensive 'mons.
Another small change that might help with DD Gyarados is trying Quick Attack over Bug Bite
on Scizor. While Quick Attack won't do tons of damage it beats out the resisted Bullet Punch any day. This might just help you out against the (admittedly) rare Gyarados.