After testing Registeel in ubers, I've decided to revise the current Registeel uber set. I've never found Shadow Claw to be very useful, and it should be emphasized more that Reigsteel is a support Pokemon and not a tank.
http://www.smogon.com/dp/pokemon/registeel
[SET]
name: Uber Support
move 1: Stealth Rock
move 2: Ice Punch / Toxic
move 3: Thunder Wave
move 4: Explosion
item: Leftovers
nature: Careful
evs: 252 HP / 24 Atk / 232 SpD
[SET COMMENTS]
<p>With its resistances to Ghost, Ice, and Dragon, immunity to Toxic, fantastic defenses, and access to useful support moves like Stealth Rock and Thunder Wave, Registeel can be a very effective team supporter in ubers. Stealth Rock is an always-useful support move that is less accessible in ubers than it is in OU. Thunder Wave is an invaluable move against the many sweepers of ubers, while Toxic breaks down walls and Groudon. Explosion is always a worthwhile choice to sacrifice Registeel once its purpose has been fulfilled, and it also helps to keep Pokemon like Mewtwo and Kyogre at bay, though Thunder Wave can do that already. Protect is another option to scout Choice attackers, and gain a small bit of recovery.</p>
http://www.smogon.com/dp/pokemon/registeel
[SET]
name: Uber Support
move 1: Stealth Rock
move 2: Ice Punch / Toxic
move 3: Thunder Wave
move 4: Explosion
item: Leftovers
nature: Careful
evs: 252 HP / 24 Atk / 232 SpD
[SET COMMENTS]
<p>With its resistances to Ghost, Ice, and Dragon, immunity to Toxic, fantastic defenses, and access to useful support moves like Stealth Rock and Thunder Wave, Registeel can be a very effective team supporter in ubers. Stealth Rock is an always-useful support move that is less accessible in ubers than it is in OU. Thunder Wave is an invaluable move against the many sweepers of ubers, while Toxic breaks down walls and Groudon. Explosion is always a worthwhile choice to sacrifice Registeel once its purpose has been fulfilled, and it also helps to keep Pokemon like Mewtwo and Kyogre at bay, though Thunder Wave can do that already. Protect is another option to scout Choice attackers, and gain a small bit of recovery.</p>