An OU team awaiting your help!

Hey guys. I'm getting used to the competitive battle scene but was wondering if some of you more experienced guys could help. This team has been working great for me. Winning about 80% of matches on Smogan's Server.

My lead, well if there isn't an Infernape or Tyranitar in the opposing team. It can set up SR, get a wish in and with serene grace, give a ailment to the opposing Pokemon.

Copper (Jirachi) @ Leftovers
Trait: Serene Grace
EVs: 252 HP / 224 SDef / 32 Spd
Careful Nature
- Stealth Rock
- Iron Head
- Body Slam
- Wish

Sapphire (Gyarados) (M) @ Leftovers
Trait: Moxie
EVs: 56 HP / 252 Atk / 202 Spd
Adamant Nature
- Waterfall
- Substitute
- Bounce
- Dragon Dance

Emerald (Breloom) @ Leftovers
Trait: Technician
EVs: 4 HP / 252 Atk / 252 Spd
Adamant Nature
- Spore
- Bullet Seed
- Mach Punch
- Swords Dance

Bronze (Mamoswine) (M) @ Life Orb
Trait: Thick Fat
EVs: 252 Atk / 4 Def / 252 Spd
Jolly Nature
- Ice Shard
- Icicle Spear
- Superpower
- Earthquake

Silver (Magnezone) @ Choice Specs
Trait: Magnet Pull
EVs: 148 HP / 252 SAtk / 108 Spd
Modest Nature
- Volt Switch
- Hidden Power [Fire]
- Thunderbolt
- Flash Cannon

Gold (Latias) (F) @ Leftovers
Trait: Levitate
Shiny: Yes
EVs: 252 HP / 4 SAtk / 252 Spd
Timid Nature
- Calm Mind
- Substitute
- Recover
- Dragon Pulse


Anyway please share your thoughts and help me improve!

Updated!

Jirachi is fine, except for fire punch...I am not sure as to why you have this. I am thinking that it is for all those ferrothorns out there, but perhaps Jirachi is not the best pokemon for this. Even as a counter to Magneton/zone, you'll be KO'd before you get to KO them. Also, perhaps shifting some EVs to defense wouldn't hurt, either.

Gyarados is good, but bounce...I know that some (few) Gyarados bear it, but it is easy to counter, and is just an opportunity to set-up if survived. I'm also not sure about the majority of EVs (or even (m)any at all being for HP). Bounce to "catch them off-guard" is also not a good strategy at all, as it is easily countered for the 1 second of skepticism that it causes.

Breloom is a good choice, and poison heal is fine. However, my personal preference is technician Breloom. In this case, spore can be kept, and then have bullet seed, mach punch and bulk up for fearsome combos. Life orb.
If you are set upon using toxic orb, it is fine. It is up to you if you keep facade or Seed Bomb, but on raw power, Facade is best. It also works best with drain punch.

Mamoswine is clear.

Magnezone is okay, but Thunder works only against rain teams with its poor accuracy. That being said, you would feel disappointed if you bear only T-bolt in the rain. However, averaging gives T-bolt advantage (120*.75 = 95; 95*1=95). Also, NEVER IGNORE STATISTICS. You are better off with T-bolt's safety over risk + benefit of Thunder.

Finally, you may wish to put a few of those EVs onto SpA with Latias (Calm mind is more effective with higher stats, due to higher products, it is simply mathematics). Also, add HP-F over something, perhaps?

Overall, the team is fairly solid. A few adjustments could increase the win-count significantly, however. Mamoswine and Latias have good movesets (though Latias has only 1 Damage-Dealing Attack) and most adjustments are EVs. Nonetheless, I still push for my advice, as the team would benefit from it.

If you have any further questions or feel that I am making a terrible analysis somewhere, please feel free to contact me or post a reply.

More elaboration on to what Squirrelfeet said:

Jirachi only needs 32 Speed EVs to outspeed Jolly Tyranitar, so the preferred EV spread is 252 HP/224 SDef/32 Spe. It's more of a support mon, so Attack EVs usually aren't needed. Also, the lack of STAB really hurts here, so use Iron Head over Fire Punch or Stealth Rock so that Jirachi can execute Paraflinch.

Even though Bounce has the tendency to draw in Pokemon that resist Flying, it's still viable on Gyarados because it's the only offensive Flying STAB it learns. It also has a 30% chance of paralysis. This EV spread is preferred on Gyarados for more initial Speed and power: 56 HP/252 Atk/204 Spe.

I agree with Squirrelfeet on Breloom. Techniloom is certainly viable this time around to boost the power of its weaker moves. That, and your current Breloom set is completely walled by Ghosts:
-Swords Dance/Low Sweep
-Bullet Seed
-Mach Punch
-Spore/Stone Edge
Nature: Adamant/Jolly
EVs: 4 HP/252 Atk/252 Spe
Item: Life Orb/Choice Band
Ability: Technician

or
-Bullet Seed
-Low Sweep/Force Palm
-Stone Edge
-Spore
Nature: Jolly
EVs: 4 HP/252 Atk/252 Spe
Item: Choice Scarf
Ability: Technician

I also agree on Magnezone; Thunder has Focus Blast level accuracy outside of rain teams, so you're better off with Thunderbolt. Magnezone isn't also very fast to begin with, so a bulky spread is preferred: 148 HP/252 SAtk/108 Spe.

On Latias, a bulky spread is preferred for a CM set because it takes advantage of Latias' greater bulk compared to Latios. Using an offensive spread on it makes Latias face stiff competition with Latios.

I cannot help but be completely outclassed by PlatinumDude's more detailed analysis. All I can do is simply agree 100% with his comments...