Pokémon Metagross

[Clone]

Just a little tiny nit pick, Zapdos' SpDef didn't drop cos of Sheer Force :p.

Good sets and a scary ass mon regardless of the set, not sure if mentioned already but would a GK set be worth considering or is it simply outclassed?

Grass knot is a viable option to lure in bulky waters + hippo, but from my personal experience (I have a lot), it's almost always an inferior option to Ice Punch, or even bullet punch, as the former gets better coverage and hits dragons and grounds harder than any other move, while the latter revenge kills faster, weakened things.
Metagross's best teammates are one that capitalize on his wallbreaking capabilities, and one that help him do this, which includes mons that best bulky waters.

 

[Ze Diglett]

Good sets and a scary ass mon regardless of the set, not sure if mentioned already but would a GK set be worth considering or is it simply outclassed?

Grass Knot is pretty viable on a Mega MixGross set since it hits bulky Water and Ground types that otherwise wall Metagross (Rotom-W, Mega Slowbro, Quagsire).

 

[ohgeedubs]

Toxic does nothing to Ferro and Skarm (both of which can be beaten with Hammer Arm) and Slowbro (non mega/CM) doesn't care care that much about Toxic as its mostly a damage sponge pivot with Regenerator anyway.

I'm not sure about Cress, is that actually used a lot?

Gyarados, won't like to switch in on Metagross as it doesn't want to take any unnecessary damage plus it will have to play mindgames with mega evolving to not get wrecked by Zen Headbutt or Hammer Arm.

I suppose it could set up on Metagross if it intimidates him but still, toxic is far too situational, simply running Thunderpunch would be a better choice if Gyarados is a problem to your team.

Re: Skarm/Ferro: That's why I said run it over Bullet/Ice Punch, not Hammer arm... as for Slowbro, it does still help (I mean Hasty GK doesn't even 2hko, imo toxic hurts more in the long run), especially when you have another pokemon that slowbro needs to check - this is when toxic pressure > the damage GK you deliver that slowbro can regen off.

Cress is not terribly common, but certain builds use it as their catch-all new mega counter (thing even beats greninja 1v1 via certain spreads), and was gaining popularity when mence was in the tier. Anyway, I see it enough that imo, you should have a plan and a back-up plan to break through it for Hyper Offensive/Offensive teams (along w/ similar pokes like Mew).

I'm not saying Gyara can switch in, but after Meta gets a kill, I'd rather not be put into an annoying 50/50 of whether they mega evolve or not. (Lum hurts, but generally +1 Gyara is easier to handle han +1 M-Gyara). Anyway, toxic isn't situational. If anything, it's way more commonly useful as an option, because it cripples tons of counters to gross, and nearly all checks. A common situation is a something like a defensive poke trying to recover-stall your last two pokes, and neither can beat it on their own. So toxic w/ Meta, pressure with coverage move, and then last poke kills.

Toxic isn't > GK necessarily, since GK does do a lot to Bro, but Thunderpunch is awful, c'mon.

Actually Mega Meta can beat Ferro / Skarm with Hammer Arm. (It is Super Effective on the former and the Speed drop will eventually cause Mega Meta to be slower than Skarm so that it gets destroyed by Hammer Arm after Roosting). Gyarados takes a lot of damage coming into Metagross's attack anyway, especially if you haven't Mega Evolved yet (since Clear Body negates Stat drops). Mega Slowbro(ken) doesn't care about Toxic if it is the CroBro set while regular Slowbro and Cresselia can heal up with their recovery and switch out before Toxic damage builds up.

That's why I said Tox > ice punch, not hammer arm.

Gyara takes a lot, but you get put into a 50/50 (do they mega or not?) when it comes in after a kill. Very annoying for offensive teams which generally discourage set-up through pure damage.

The faster you cause crobro to rest, the easier it is to beat it with a teammate. And what, were you planning on beating crobro with grass knot?

Just to be clear, toxic isn't for beating all these pokemon one-vs-one, it's as a support to soften all of mega-meta's checks for other teammates (esp on Hyper offense), and is more universally useful than grass knot (but not better per se), in the sense that it's not just for 1-2 pokes.

Anyway, I'm just putting it out there as an option that I genuinely believe to be better than GK and sometimes Ice punch for particular teams (esp certain offensive builds). Just throwing it out there. If you think it's a bad option in all cases, your loss.

 

[5th]

PuP isn't really viable on Metagross, imo. I mean, I guess you could argue that in theory that it can potentially run over slower teams as they struggle to tank boosted attacks, but that's rarely ever the case and you're wasting a moveslot that can be put to better use with additional coverage. It's highly situational, virtually useless against offense, and a terrible choice for a moveslot when Metagross should be smashing holes into teams, and you're not going to be smashing anything with an non-STAB 40 base power attack. Not saying the move is bad, but it's not really something Metagross should be running.

 

[GateRH]

Well, I really want to build a team based on M-Metagross, but I'll wait for see if he is going to be banned because I got no doubt about that. Anyway, I would consider in use Rock Polish and expend EVs in HP/Speed and Attack, and with that, start the game using Rock Polish, probably with a nice HP the Metagross will resist to a good number of attacks, and after that, use him to sweep with fisical attacks, Earthquake, Meteor Mash and Ice Punch for Garchomps. It's a really very useful pokemon~

 

[jnrust]

I've been tweeking this set, and I just want some opinions on it.
Metagross @ Metagrossite
Ability: Clear Body
EVs: 228 HP / 252 Atk / 28 Spd
Naughty / Adamant
- Agility / Rock Polish
- Zen Headbutt / Iron Head
- Hammer Arm / Earthquake
- Grass Knot / Ice Punch / Toxic

 

[Force Majeure]

Well, I really want to build a team based on M-Metagross, but I'll wait for see if he is going to be banned because I got no doubt about that. Anyway, I would consider in use Rock Polish and expend EVs in HP/Speed and Attack, and with that, start the game using Rock Polish, probably with a nice HP the Metagross will resist to a good number of attacks, and after that, use him to sweep with fisical attacks, Earthquake, Meteor Mash and Ice Punch for Garchomps. It's a really very useful pokemon~

I agree that it's useful, but I wouldn't hold off on creating a team around it because I doubt very much that it will be banned, let alone suspected.

I've been tweeking this set, and I just want some opinions on it.
Metagross @ Metagrossite
Ability: Clear Body
EVs: 228 HP / 252 Atk / 28 Spd
Naughty / Adamant
- Agility / Rock Polish
- Zen Headbutt / Iron Head
- Hammer Arm / Earthquake
- Grass Knot / Ice Punch / Toxic

That's quite a bit of slashing going on; I think it might be a good idea to edit your post to clarify exactly what you want to be doing with M-Gross, what the EVs do, and which attacks cover which threats. I'm somewhat set-up skeptical about some of the slashes, esp. your choice to slash both STABs in the same slot.

 

[RoyalDispenser]

I've been having decent success with this set.

Metagross @ Metagrossite
Ability: Clear body
EVs: 252 Atk, 4 SpD, 252 Spe
Jolly
- Zen Headbutt
- Pursuit
- Ice Punch
- Earthquake

I honestly don't know the importance of having to have a steel STAB. Dark types are usually dueled with something that EQ handles better, fairies can't do anything to you other than mega diancie, (who would never switch in and fears EQ, or in altaria's case.. ice punch) bullet punch isn't that stong unboosted (which unforunantly it cannot boost outside of lolup-punch and RNG with meteor mash), I'm just not seeing it.

 

[jnrust]

I agree that it's useful, but I wouldn't hold off on creating a team around it because I doubt very much that it will be banned, let alone suspected.


That's quite a bit of slashing going on; I think it might be a good idea to edit your post to clarify exactly what you want to be doing with M-Gross, what the EVs do, and which attacks cover which threats. I'm somewhat set-up skeptical about some of the slashes, esp. your choice to slash both STABs in the same slot.

Let's see, I guess I'll settle with this set.
Naughty Nature
- Zen Headbutt / Iron Head
- Hammer Arm
- Grass Knot
- Agility

As seen in a previous post:

Metagross-Mega @ Metagrossite
Ability: Tough Claws
EVs: 228 HP / 252 Atk / 28 Spe
Adamant Nature
- Rock Polish
- Meteor Mash
- Zen Headbutt
- Ice Punch / Earthquake

Been messing around in the calculator and came up with this spread. Id like a few opinions on this before I add it to the OP. 28 Speed EVs outspeed scarfed base 110s after a rock polish w/ an adamant nature. rest gos into HP for bulk.

Other benchmarks:
116 EVs outspeed positive base 100s post mega
176 EVs outspeed neutral base 100s post mega
188 EVs outspeed jolly excadrill post mega

84 EVs outspeed uninvested base 80s (few more to creep)
172 EVs outspeed uninvested Lando T

Im thinking 116 might be the best option, as it gives a good speed number post mega should you not be able to get off a Rock Polish. 84 and 172 also seem like decent numbers should you be worried about things before you get the mega off

Obviously, the first thing would be to fire off an Agility/Rock Polish, allowing you to outspeed Scarf 110s. For the first variant, Grass Knot was put in mainly to take on Mega Slowbro. The reason I went Naughty vs Adamant in this case would be in the case of MegaCrobro already have a +1 in its belt. On the turn Grass Knot is used, Megabro would be at +2, and then rest on the second Grass Knot.
0 SpA Tough Claws Metagross Grass Knot (100 BP) vs. +1 252 HP / 4 SpD Mega Slowbro: 160-190 (40.6 - 48.2%)
0 SpA Tough Claws Metagross Grass Knot (100 BP) vs. +2 252 HP / 4 SpD Mega Slowbro: 120-142 (30.4 - 36%) -- 44.9% chance to 3HKO
To me, that is a huge difference compared to Adamant Nature.
0- SpA Tough Claws Metagross Grass Knot (100 BP) vs. +2 252 HP / 4 SpD Mega Slowbro: 108-128 (27.4 - 32.4%) -- guaranteed 4HKO
While not reliable due to the 3HKO only happening at a 44.9%, it is formidable, because Mega Slowbro's can PP Stall against Adamant Grass Knot whilst Naughty can potentially KO Megabro.
Hammer Arm is used mainly to take on Pokemon that take the other moves well. Should you run into Mega-Gyarados, Grass Knot will net the 2HKO on Offensive Dragon Dance sets, but for Bulky Dragon Dance Set, Naughty Nature is better, in my opinion:
0 SpA Tough Claws Metagross Grass Knot (120 BP) vs. 88 HP / 0 SpD Mega Gyarados: 192-226 (54.3 - 64%) -- guaranteed 2HKO
0- SpA Tough Claws Metagross Grass Knot (120 BP) vs. 88 HP / 0 SpD Mega Gyarados: 172-204 (48.7 - 57.7%) -- 94.1% chance to 2HKO
I will say you can use Hammer Arm; however, there will be situations where you can be at -1 due to Regular Gyarados Intimidate, and the Spd drop may leave you open to KOs from Revenge Killers should Gyarados hit you with the Crunch
192+ Atk Mold Breaker Mega Gyarados Crunch vs. 224 HP / 0 Def Metagross: 222-264 (62.1 - 73.9%)
252+ Atk Tough Claws Metagross Hammer Arm vs. 88 HP / 4 Def Mega Gyarados: 320-378 (90.6 - 107%) -- 43.8% chance to OHKO
-1 252+ Atk Tough Claws Metagross Hammer Arm vs. 88 HP / 4 Def Mega Gyarados: 214-252 (60.6 - 71.3%)
Another thing to note at +1, you still outspeed Life Orb Greninja should you use Hammer Arm previously, and net another KO with said Hammer Arm. Also, with 28 Spd EVs, you'll Outspeed Choice Band Dragonite and most likely net a 2HKO.
252+ Atk Tough Claws Metagross Zen Headbutt vs. 0 HP / 4 Def Multiscale Dragonite: 107-126 (33.1 - 39%)
252+ Atk Tough Claws Metagross Zen Headbutt vs. 0 HP / 4 Def Dragonite: 214-253 (66.2 - 78.3%)
It seems that Iron Head is more useful, but there are situations where Zen Headbutt is more useful, mainly Mega-Venasaur, Mega-Manectric, Thundurus, and (after speed boost) maybe Talonflame, but that is 50/50. Rotom-W is a possibility, but that's debatable.
252+ Atk Tough Claws Metagross Zen Headbutt vs. 0 HP / 4 Def Talonflame: 271-321 (91.2 - 108%) -- 50% chance to OHKO
252+ Atk Choice Band Talonflame Flare Blitz vs. 224 HP / 0 Def Metagross: 332-392 (92.9 - 109.8%) -- 56.3% chance to OHKO
252+ Atk Tough Claws Metagross Iron Head vs. 0 HP / 4 Def Talonflame: 135-160 (45.4 - 53.8%) -- 46.9% chance to 2HKO
252+ Atk Tough Claws Metagross Zen Headbutt vs. 0 HP / 4 Def Conkeldurr: 428-506 (121.9 - 144.1%) -- guaranteed OHKO
252+ Atk Tough Claws Metagross Iron Head vs. 0 HP / 4 Def Conkeldurr: 214-253 (60.9 - 72%) -- guaranteed 2HKO
252+ Atk Tough Claws Metagross Zen Headbutt vs. 0 HP / 4 Def Thundurus: 274-324 (91.6 - 108.3%) -- guaranteed OHKO after Stealth Rock
252+ Atk Tough Claws Metagross Iron Head vs. 0 HP / 4 Def Thundurus: 137-162 (45.8 - 54.1%) -- guaranteed 2HKO after Stealth Rock
252+ Atk Tough Claws Metagross Zen Headbutt vs. 252 HP / 212+ Def Rotom-W: 147-174 (48.3 - 57.2%) -- 41% chance to 2HKO after Leftovers recovery
-- 91.8% chance to 2HKO for ChestoRest variants
252+ Atk Tough Claws Metagross Iron Head vs. 252 HP / 212+ Def Rotom-W: 36-43 (11.8 - 14.1%)
I will say, if you don't use Iron Head, then Psychic types can come in safely.
Earthquake can replace Hammer Arm if you don't like the 90 Accuracy, and would want to be able to KO Mega-Charizard X and whatnot.
252+ Atk Metagross Earthquake vs. 0 HP / 4 Def Mega Charizard X: 238-280 (80.1 - 94.2%) -- guaranteed OHKO after Stealth Rock
252+ Atk Tough Claws Metagross Hammer Arm vs. 0 HP / 4 Def Mega Charizard X: 158-186 (53.1 - 62.6%) -- guaranteed 2HKO after Stealth Rock
More often than not, Hammer Arm is more useful as it'll net KOs much more easily that Earthquake couldn't; however, Earthquake is still viable in certain situations. Ice Punch can be used in place of Grass Knot to take on Defensive Landorus-T as well as Scarfchomp, but that would leave you as setup fodder for Mega Slowbro. So yeah, that is as much as I can think of when it comes to Mega-Metagross. There may be other situations, but I need to eat.
EDIT: After looking through, You can have Iron Head replace Hammer Arm instead. inevitably, Very much like one of the previous posts except with Grass Knot instead of Earthquake.
- Agility
- Zen Headbutt
- Iron Head
- Grass Knot / Ice Punch
WELP

 

[Mikroturbulence]

OP you may wanna remove the replay as it's honestly not a good demonstration of anything. Also it's quite embarassing how you kept harping on about not getting a spdef drop with lando when you have sheer force LOL

 

[Wargreymon]

Why is bullet punch even slashed? Metagross pretty much needs to always run meteor mash, zen headbutt, and a move for steels (eq/hammer arm). This means the final slot is extremely precious in terms of coverage and having another steel move just makes Metagross extremely predictable. I know it's hardly an unpredictable pokemon anyway, but with two steel moves it's much easier to wall. Even with tough claws it's still a weak move, and the only reason it's ever used on regular is because of its ass base speed. 110 is fast enough to make priority obsolete in most cases. Grass knot/Ice punch are far more valuable and Metagross really needs a slot dedicated to this type of coverage.

Maybe I'm missing something here that's really obvious, but I don't think BP is even worth considering.

 

[AM]

Why is bullet punch even slashed? Metagross pretty much needs to always run meteor mash, zen headbutt, and a move for steels (eq/hammer arm). This means the final slot is extremely precious in terms of coverage and having another steel move just makes Metagross extremely predictable. I know it's hardly an unpredictable pokemon anyway, but with two steel moves it's much easier to wall. Even with tough claws it's still a weak move, and the only reason it's ever used on regular is because of its ass base speed. 110 is fast enough to make priority obsolete in most cases. Grass knot/Ice punch are far more valuable and Metagross really needs a slot dedicated to this type of coverage.

Maybe I'm missing something here that's really obvious, but I don't think BP is even worth considering.

Bullet Punch improves its effectiveness against faster paced offense instead of being a liability against stuff like Weavile when not running Agility/Rock Polish sets.

As mentioned the only thing pretty much mandatory is Steel STAB which is usually Meteor Massh/Iron Head, and Zen Headbutt. The last two is coverage depending on team and whatever else is necessary.

 

[Wargreymon]

I thought a steel wrecking move was also mandatory? Otherwise Heatran is free to switch in as it pleases to set up rocks or dent a switch in, Magnezone can trap and beat Metagross 1v1 which is hilarious, and Bisharp either sets up swords dance in your face or just kills you with pursuit. Considering the relevance of these steels in OU I'd honestly argue that a slot dedicated to eq/hammer arm is mandatory.

Edit: Excadrill outside of sand then beats Metagross too.

I'm getting sidetracked here. On the topic of BP, that's fair enough. I'll admit that I forgot about threats like Weavile as I haven't seen many lately.

 

[AM]

I thought a steel wrecking move was also mandatory? Otherwise Heatran is free to switch in as it pleases to set up rocks or dent a switch in, Magnezone can trap and beat Metagross 1v1 which is hilarious, and Bisharp either sets up swords dance in your face or just kills you with pursuit. Considering the relevance of these steels in OU I'd honestly argue that a slot dedicated to eq/hammer arm is mandatory.

I'm getting sidetracked here. On the topic of BP, that's fair enough. I'll admit that I forgot about threats like Weavile as I haven't seen many lately.

It's usually Hammer Arm > EQ since it hits just about all those things you mentioned instead of EQ that doesn't have a chance of breaking Ferro and allows a free hit for Balloon Tran and Balloon Excadrill. I just put coverage cause people have a tendency to pick between the two more so than a concrete one. But yeah third slot would be one of those two more so Hammer Arm than EQ.

 

[Oathkeeper]

I've found the Metagross that I have here tends to be very effective as a physical sweeper. Once it's Mega-Evo takes hold, it's pretty hard to stop. I guess you could thrown in Pursuit instead of Ice Punch or Earthquake, but this set is dominant.

Metagross @ Metagrossite
Ability: Clear Body
EVs: 252 Atk / 4 HP / 252 Spe
Jolly Nature
- Meteor Mash
- Zen Headbutt
- Earthquake
- Ice Punch

 

[Karxrida]

I've found the Metagross that I have here tends to be very effective as a physical sweeper. Once it's Mega-Evo takes hold, it's pretty hard to stop. I guess you could thrown in Pursuit instead of Ice Punch or Earthquake, but this set is dominant.

Metagross @ Metagrossite
Ability: Clear Body
EVs: 252 Atk / 4 HP / 252 Spe
Jolly Nature
- Meteor Mash
- Zen Headbutt
- Earthquake
- Ice Punch

That's a pretty standard set, except Hammer Arm > Earthquake since it lets you beat Skarmory and Ferrothorn.

Also AM, Weavile can't exactly threaten Mega Metagross unless it's sufficiently weakened. Its Knock Off is weaker than Bisharp's Sucker Punch, and Bisharp can't even guarantee an OHKO on Metagross with it :/.

252+ Atk Life Orb Bisharp Sucker Punch vs. 0 HP / 0 Def Mega Metagross: 257-304 (85.3 - 100.9%) -- 6.3% chance to OHKO

 

[Harumonia]

and Bisharp can't even guarantee an OHKO on Metagross with it :/.

252+ Atk Life Orb Bisharp Sucker Punch vs. 0 HP / 0 Def Mega Metagross: 257-304 (85.3 - 100.9%) -- 6.3% chance to OHKO

Don't forget that many Bisharps are opting to utilize a Jolly nature over Adamant.
252 Atk Life Orb Bisharp Sucker Punch vs. 0 HP / 0 Def Metagross: 234-276 (77.7 - 91.6%) -- guaranteed 2HKO

 

[Mr. Degradation]

Does anybody have any sweet utility builds? The utility build on the Smogdex interested me, are there any variants of that anyone is using?

 

[56k]

VS my stall team this thing brings an awful lot of matches down to "did it flinch or not" - "did it get an atk boost or not". No joke it breaks through max defense gliscor AND max defense sableye if it gets a hax. I'm afraid to run slowbro because I always recommend the grass knot set to other people <_< this mega is beastly. I think I'm going to run 252 HP 252 Atk Adamant and see what I can do with it on my next team.

 

[OLD GREGG (im back baby)]

If possible mega gross really appreciates the baton pass. I've used Ninjask to BP Hone Claws and speed boosts in the past, it's pretty much GG at that point. This is very situational but if you can get a clean BP over to Mega Gross it can be nearly impossible to revenge.


Also worth noting that with BP support, you can have more defensive investments and more freedom with your moveset, which IMO is a huge plus! Mega Gross appreciates the accuracy boost most of all, though. When taking BP into consideration for Mega Gross then Hone Claws should be the default choice instead of swords dance or agility.

 

[Turducken64]

Is a steel stab move really needed in mega meta as it can now run another coverage move and only misses out on fairies since fighting attacks hit everything his steel stab wants to hit. Something like:

Metagross-Mega @ Metagrossite
Ability: Tough Claws
EVs: 252 Atk / 4 SpA / 252 Spe
Naive Nature
- Zen Headbutt
- Ice Punch
- Hammer Arm
- Grass Knot

Seems pretty effective as it only gains better coverage against common switch ins. The only loss is the power and potential boosts you can get from meteor mash but you gain the ability to lure in bulky waters and grounds much more effectively. Wirth this set metagross gives up the ability to sweep but can now dismantle annoying cores with ice punch and grass knot this set pairs well with something that enjoys the removal of bulky water or ground so some mons like SD talonflame or BD azumarill both pair well with this metagross. Thunder Punch is another option but grass knot is usually the better option hitting many bulky waters such as mega slowbro, quagsire and whatnot harder.

 

[Prinz]

I'd mention HP Fire on the notable moves as well. It 2HOKes Ferrothorn and Skarmory who otherwise are quite troublesome, and it's a good choice in general if you don't want to run Magnezone to beat them.

 

[Vengeance417]

I'd mention HP Fire on the notable moves as well. It 2HOKes Ferrothorn and Skarmory who otherwise are quite troublesome, and it's a good choice in general if you don't want to run Magnezone to beat them.

Note that if you run HP Fire, you're guaranteed to lose speed ties with the other base 110s in the tier, such as Gengar, Mega Gallade, the Latis, ect. Either way, HP Fire is highly unexpected and is an interesting option.

 

[firehusky]

I'd mention HP Fire on the notable moves as well. It 2HOKes Ferrothorn and Skarmory who otherwise are quite troublesome, and it's a good choice in general if you don't want to run Magnezone to beat them.

No, HP Fire is horrible on metagross. HP fire hits ferrothorn and skarmory, but those are basically the only mons it hits. Hammer arm beats both of those too, while also hitting steels types like heatran, bisharp, and magnezone.

Uninvested HP fire is super weak:
0 SpA Mega Metagross Hidden Power Fire vs. 252 HP / 168 SpD Ferrothorn: 136-164 (38.6 - 46.5%) -- guaranteed 3HKO after Leftovers recovery
0 SpA Mega Metagross Hidden Power Fire vs. 252 HP / 4 SpD Skarmory: 122-144 (36.5 - 43.1%) -- 98.2% chance to 3HKO after Leftovers recovery
0 SpA Mega Metagross Hidden Power Fire vs. 4 HP / 0 SpD Bisharp: 122-144 (44.8 - 52.9%) -- 25.8% chance to 2HKO
0 SpA Mega Metagross Hidden Power Fire vs. 0 HP / 0 SpD Magnezone: 100-118 (35.5 - 41.9%) -- guaranteed 3HKO
0 SpA Mega Metagross Hidden Power Fire vs. 248 HP / 176 SpD Mega Scizor: 156-184 (45.4 - 53.6%) -- 34% chance to 2HKO

Compared to hammer arm
252 Atk Tough Claws Mega Metagross Hammer Arm vs. 252 HP / 88+ Def Ferrothorn: 212-250 (60.2 - 71%) -- guaranteed 2HKO after Leftovers recovery
252 Atk Tough Claws Mega Metagross Hammer Arm vs. 248 HP / 0 Def Heatran: 300-354 (77.9 - 91.9%) -- guaranteed 2HKO after Leftovers recovery
252 Atk Tough Claws Mega Metagross Hammer Arm vs. 0 HP / 4 Def Magnezone: 278-328 (98.9 - 116.7%) -- 93.8% chance to OHKO
Against skarmory, keep using hammer arm until you are slower than skarmory, then catch him on the roost (loses it's flying type).
Do I even need to calc against bisharp lol

 

[Prinz]

Nobody said you are using HP Fire Metagross without any investiment, you need infact as you pointed out some EVs in SAtk to 2HKO both Skarmory and Ferrothorn. Hammer Arm is probably the best option, but I can see a set with Grass Knot and HP Fire working well on Metagross, being able to lure some of counters and checks like Hippowdon, Skarmory, Ferrothorn and Quagsire. I mean, if Thunder Punch is mentioned in the notable moves, I'd mention HP Fire as well. Im not saying that HP Fire is better than Hammer Arm, who is overall more reliable, but I guess that a set of Grass Knot / HP Fire / Meteor Smash and Zen Headbutt / EQ (but if you choose to run EQ you are walled by Rotom-W which sucks) can have its own niches.