SL Sunday: Mega Pinsir

Hello everyone, Steak is here!  I would like to regularly be involved in SL but two things have been holding me back.  One is going on to SL in the first place and the other is my lack of teambuilding.  To fix these issues, I am going to do a thing where every Sunday I come on and make a team around a pokemon that was either suggested to me or that I find interesting.  I am going to try to follow a four OU limit and I am not going to use legends as I may use these teams in gym battles in the future.  This week, I am going to spotlight Mega Pinsir.  Anyways, after that long introduction, to the team:

Pinsir-Mega @ Pinsirite  
Ability: Hyper Cutter  
EVs: 252 Atk / 4 Def / 252 Spe  
Jolly Nature  
- Swords Dance  
- Return  
- Earthquake  
- Quick Attack  

Magnezone @ Choice Scarf  
Ability: Magnet Pull  
EVs: 252 SpA / 4 SpD / 252 Spe  
Timid Nature  
- Volt Switch  
- Flash Cannon  
- Thunderbolt  
- Hidden Power [Fire]  

Rotom-Wash @ Chesto Berry  
Ability: Levitate  
EVs: 252 HP / 4 SpA / 252 SpD  
Calm Nature  
- Volt Switch  
- Hydro Pump  
- Will-O-Wisp  
- Rest  

Donphan @ Life Orb  
Ability: Sturdy  
EVs: 252 HP / 252 Atk / 4 SpD  
Adamant Nature  
- Stealth Rock  
- Rapid Spin  
- Earthquake  
- Knock Off  

Volcarona @ Lum Berry  
Ability: Flame Body  
EVs: 252 SpA / 4 SpD / 252 Spe  
Modest Nature  
- Quiver Dance  
- Fiery Dance  
- Giga Drain  
- Bug Buzz  

Sylveon @ Leftovers  
Ability: Pixilate  
EVs: 252 HP / 4 SpA / 252 SpD  
Calm Nature  
- Wish  
- Heal Bell  
- Toxic  
- Hyper Voice  


I would like to know if I can use this team effectively in the meta, what its major weaknesses are and what I can do to improve it without breaking my guidelines set above.  Thank you for any suggestions you post below.

Edit: Post your requests for next week and I'll look through them.

This is a pretty solid team. I don't see any weaknesses, but the best way to see some weaknesses is to battle with it. Maybe you find out your team is heavily weak against stall for example. The typing is balanced and there is no lack in either physical or special attackers.