Steelix

Sturdy
OHKO moves will fail.
Rock Head
Recoil moves have no recoil.
Type Tier
Steel / Ground BL
Statistics
Min- Min Max Max+
HP
75
- 291 354 -
Atk
85
185 206 269 295
Def
200
392 436 499 548
SpA
55
131 146 209 229
SpD
65
149 166 229 251
Spe
30
86 96 159 174
Name Item Ability Nature

Standard wall

Leftovers Sturdy Impish
Moveset EVs
~ Earthquake
~ Toxic / Hidden Power Rock
~ Roar
~ Rest / Explosion
252 HP / 36 Atk / 220 SpD

It's pretty easy to send it in against Normal and Flying hits, Electrics, Metagross or Snorlax. From there, attack accordingly, Toxic Waters and other vulnerable Pokémon you cannot really hurt, and Explode when you're through. A very simple concept, the only thing that's really wrong with Steelix as a wall is its lack of instant attacking power.

Name Item Ability Nature

Choice Bander

Choice Band Rock Head Adamant / Impish
Moveset EVs
~ Earthquake
~ Iron Tail / Hidden Power Steel
~ Double-Edge / Hidden Power Rock / Rock Slide
~ Explosion
144 HP / 228 Atk / 136 SpD

This sort of solves Steelix's low Attack problem, but not completely as it's still slow and cannot hurt Waters that will predictably come in. Losing its Leftovers isn't that great either. Still, easy enough to bring in. Predict what your opponent will send in and move accordingly. Explode when you're getting low.

Other Options

There's no real alternatives for the Choice Band set. Hidden Power Rock is your only hope against Sleep Talk Zapdos, and Iron Tail hits Gengar, Aerodactyl and Regice pretty hard, among others. Block can trap something—hopefully you can get a Water, survive the Surf and Explode on them. This way can sweep your opponent with Salamence or a similar sweeper that has trouble getting past Waters. Psych Up can steal Curses from Snorlax or even Regirock. You can Roar them out afterwards, or just own them one on one.

EVs

For walls like Steelix HP is one of your most important stats so you should max it. The rest is up to personal preference, do you want to hit harder or defend stronger? Either way, always go with Impish; this Pokémon’s role is a wall, it should never be used as a sweeper. You may also want to consider giving it a small amount of Speed EVs to outrun Snorlax and friends.

Opinion

An excellent wall. He sponges a very big amount of standards, has a STAB Earthquake to beat Metagross and more often than not Tyranitar and he can Explode. A great pseudo-hazer for Snorlax and Baton Pass Zapdos as well. The reason he isn't used much is because he really sucks at attacking. 85 base Attack is not impressive at all, and quite a few standards laugh at him. That doesn't mean he is unusable though—he is one of the best BLs available. Also a great wall for Raikou that don't have Hidden Power Water, which is virtually all of them.

Counters

Skarmory, Cloyster and Forretress can set up Spikes in its face easily without dying at all, except maybe Cloyster to Toxic. Any Water-type with decent defenses comes in easily, shrugs off hits and OHKOs or 2HKOs Steelix with Surf—think Suicune, Swampert, Milotic, Slowbro, Vaporeon, etc. Moltres can OHKO Steelix with any Fire move as long as it avoids Rock moves.

Fire and Water attacks are also going to hurt Steelix a lot, unboosted or otherwise, and any decent (non electric) Special Attack will also seriously injure this beast so either switch the hell out or explode if you feel Steelix has served it's purpose. Its physical weaknesses aren't quite as big of an issue, but a boosted Brick Break or Earthquake will beat Steelix up a bit. Beware, in particular, of Choice Band sweepers, like Aerodactyl, Medicham and Heracross.