Magic Guard isn't the problem, Rankurusu is as a whole. Rankurusu poses far to big a threat to dedicated stall teams to be dealt with consistently, because it's bulk + Recover makes it impossible for stall to wear it down through direct damage when coming off of generally weak walls, and Magic Guard makes it impossible to wear down through indirect damage. Other Magic Guard users don't pose this same threat, because they really don't have the bulk to take repeated attacks even when coming from weaker offensive stats, and lack good enough offensive stats to break stall (outside of Alakazam, who dies to a stiff breeze)
So all stall teams are 6 walls with 1 attack?
You should,in some way,be able to wear him down,and if you downright REFUSE to use an attacking mon,you can go the gimmicky way and use Worry Seed,forcing him to switch.
He'll pretty much be the last mon to die.
Last I checked, Electric/Water/Grass are fairly common and being able to stomp on most water and grass pokes is awesome. I say those are fairly important to resist as well. And that is a difference of 2% and most Scizors I think carry Choice Band/Life Orb (well, I guess some could carry Leftovers) and neither one usually (unless Kyurem has to or is behind Reflect) is going to stay in and risk Scizor Bullet Punch anyways. Both Tyranitar and Kyurem can 2 hit ko Scizor (or 1 hit ko from Tyranitar Fire Punch or fire move or if Kyurem carries Hp Fire) and most Tyranitars are bulkier than 341 hp anyways I think. Poison resist (except against Venasaur or Roserade who'd be carrying Giga Drain/Power Whip/Leaf Storm also) is not exactly exciting nor is Flying (except in Ubers against Ho-Oh, the only time you'd see Flying in OU is from Staraptor and Braviary who'd have Close Combat/Super Power). Normal is fairly rare so that also is fairly negligible. So Tyranitar has about 4 useful common resists/immunity to OU things and Kyurem has 3.
Tyranitar also can not throw out Stabbed Draco Meteors off of 130 base special attack, just saying. Tyranitar is a phenomenal Pokemon. But Kyurem is severely underrated and far, far bulkier than people give credit for. Having the same special attack as Latios but far better surviveability at a tolerable okay enough speed is pretty good. Like Latios, you can't exactly switch in safely (eating Specs Blizzards and Draco Meteors is tough) but you can't Pursuit this one very well.
And with 417 hp/256 Def behind Reflect, Choice Band Technican Bullet Punch from Scizor does 36.45-43.17% (71.94-84.89% without Reflect). Scizor with Leftovers could not 2 hit ko the above Kyurem without Stealth Rock. Tyranitar is not fond of Scizor without Fire Punch/Flamethrower/Fire Blast either.
The damage is scalable and is meant just as a comparison.
A T-tar with 252 Hp/252 Def will take like 2% less damage from that Bullet Punch than a Kyurem with 252 HP/252 Def spread.
If you want to spam Draco Meteors,you have two mons that are better in that regard:
Latios and Sazandora(Who isn't Pursuit weak)
Neither are weak to Stealth Rock so they can lob off Meteors all over the place,and with Specs,they can hit super hard. They're also faster than Kyurem.(Not to mention,using a DM makes him near useless for special attacks,which you need for Blizzard >.>)
And using Reflect to turn a 2HKO into a 3HKO isn't worth the loss in coverage unless you're using a support set.
T-tar can do a bit of damage with a STAB Stone Edge against Scizor since it's unresisted.
BandTar's Stone Edge can 2HKO Impish 252 HP/252 Def Scizor:
604 Atk vs 328 Def & 344 HP (100 Base Power): 198 - 234 (57.56% - 68.02%)
No one uses that spread on Scizor,so T-tar doesn't need a fire move to fight Scizor.(Well,Scizor can't really switch in,so it can't counter unless it switches in on a Crunch or something)
He's not crap,but he's just meh.