Bronzong
Standard Wall
Item Leftovers
Abilty Levitate
Natu Sassy
Move Set
~ Gyro Ball
~ Stealth Rock
~ Hypnosis
~ Earthquake
Bronzong is an excellent Stealth Rock user as well as an excellent wall of both physical and special attacks. With its above average defenses and plethora of resistances, Bronzong can set up rocks and put its foe to sleep with ease. Despite its mediocre Attack, Bronzong's incredibly low Speed, combined with a STAB Gyro Ball, allows it to deal respectable damage to any sweeper, and easily OHKO fast sweepers like Weavile and Scarf Gengar and 2HKO others such as Tyranitar. Earthquake allows Bronzong to hit Pokémon that resist Gyro Ball - mainly Infernape, Magnezone and Heatran (though none are OHKOed) - which would otherwise be able to take out Bronzong with little difficulty.
If you have another Stealth Rock user on your team, you can forgo Stealth Rock for the powerful finishing move Explosion. This will allow Bronzong to act as a check against any Pokemon which gives your team problems, since there are few Pokemon in OU which will not be KOed or severely crippled after being on the receiving end of what is for all intents and purposes a 500 base power attack. Alternatively, Reflect or Light Screen can be used if you feel that your team could use the support. Lum Berry is also a decent option over Leftovers if you are using Bronzong as a lead, as it will allow Bronzong to deal with sleep leads such as Gengar and Yanmega. Charge Beam is also a fine choice for the last slot, as it hits Gyarados, Yanmega, and a number of other Pokémon for super effective damage. Hidden Power Ice can also be used in the last spot to hit Salamence and Dragonite, though some Special Attack investment is needed to 2HKO them.
TrickZong
Item Macho Brace
Abilty Levitate
Natu Sassy
~ Trick
~ Stealth Rock
~ Gyro Ball
~ Earthquake / Explosion
Similar to the previous set, except Trick is being used instead of Hypnosis. While the sets are similar, they play entirely differently. Macho Brace cuts Bronzong's Speed by fifty percent, which in turn powers up Gyro Ball to extraordinary levels now that Bronzong has a 31 Speed stat. More importantly, however, is Bronzong's ability to cripple incoming sweepers by robbing them of their item and shredding any speed advantage they ever had over your other team members. For example, Bronzong will tend to draw in sweepers like Heatran or Gyarados anticipating a weak Gyro Ball. However, to their dismay, they will be forced to give up their held item in exchange for the rather limiting Macho Brace. Choice Band is also a decent option to cripple wall switch-ins such as Swampert or Dusknoir and also provides Bronzong with quite a bit of power. If you opt for Choice Band, you may want to just maximize Attack to make Bronzong a more offensive threat. The remaining portion of the set is identical to the previously discussed wall set.
The item Lagging Tail forces the holder to always move last and is a viable option over Macho Brace; however, it will not boost the power of Gyro Ball like Macho Brace will. Iron Ball is an interesting option as you can Trick it onto something with a Ground immunity and make them vulnerable to Spikes and Toxic Spikes, although it does come at the cost of Bronzong's own Levitate being nullified while it's holding it.
Screener
Item Lum Berry
Abilty Levitate
Natu Relaxed
~ Gyro Ball
~ Trick Room
~ Hypnosis / Reflect / Light Screen
~ Explosion
252 HP / 62 Atk / 104 Def / 92 SpD
While Bronzong makes a fantastic wall with its ample resistances and many support moves, it does however lack a recovery move. This set remedies that problem. Rest and Sleep Talk allow Bronzong to become the status absorber of the team while retaining its walling abilities. Rest and Sleep Talk are, obviously, the core moves of this set, allowing Bronzong to recover any damage and detrimental status it may have acquired. With its abysmal Speed, Gyro Ball can often function at maximum base power against sweepers like ScarfGar. Earthquake gives Bronzong good type coverage with its STAB move, letting it hit Pokémon that resist Gyro Ball, namely Heatran. It should be noted that this set isn't perfect; Bronzong cannot inflict much damage to many of the common sleep inducers. These include Breloom, Yanmega, Milotic, Tangrowth, and other Bronzong.
The EVs are almost identical to the first moveset. However, if you feel like this Bronzong should be your counter to the OU Dragons, use Hidden Power Ice over Earthquake. You will need 24 EVs (which you can take from Defense) and add them to Special Attack to guarantee a 2HKO on Salamence and Dragonite (though Dragonite is only 2HKOed with Stealth Rock damage). Sassy is the preferred nature for this moveset because while Relaxed is also beneficial to Bronzong by lowering the amount of damage it takes from physical attacks, Sassy is much more helpful. For example, while Relaxed lowers the amount of damage taken from Breloom's Focus Punch, it is still a 2HKO, just as it is when using Sassy nature. Also, when using Sassy, Bronzong is able to survive SpecsMence's Fire Blast, where Relaxed is unable to do so.
Torrential Zong
Item Damp Rock
Abilty Levitate
Natu Impish
~ Rain Dance
~ Explosion
~ Stealth Rock
~ Reflect / Hypnosis
Very rarely is a Pokémon perfectly suited to provide almost exactly what a particular style of team requires. Then again, not many Pokémon have the utility capacity that Bronzong possesses. The EVs are set to give Bronzong more physical bulkiness, as Rain Dance will allow it to survive most Fire Blasts and Flamethrowers, the common special attacks thrown at it. 128 Attack is given to give a boost to Explosion, allowing it to always OHKO 252 HP / 0 Def Snorlax, a common deterrent to Rain Dance teams.
Rain Dance teams require a few factors to be ultimately successful: long lengths of Rain Dance, Stealth Rock, and a safe switch in for sweepers to allow them to wreak havoc. Bronzong sets up Rain Dance for 8 turns with Damp Rock, allows efficient switching in by Exploding (possibly on a counter), can lessen the threat of priority attacks with Reflect, and sets up Stealth Rock, so Kingdra can get that guaranteed OHKO on Metagross and Kabutops can get that guaranteed OHKO on other Bronzong. Hypnosis' reliability is once again questionable, and generally the off chance of sleeping a threat is not worth the reliable protection Reflect affords.
The reason Gyro Ball and Hidden Power Ice are ignored here is that this Bronzong isn't supposed to be an attacker or last a long time, so these moves are unnecessary. The sole purpose of this Bronzong is to come in sometime in the early to middle parts of battle (note it is not an effective lead), set up Stealth Rock, use Rain Dance, possibly set up Reflect or Hypnotize the opponent, and then Explode away, leaving 6 turns of Rain for sweepers such as Kingdra, Ludicolo, Kabutops, or Omastar..
Fuente smogon.com