Although Stormbreaker and Mjolnir have very similar properties and powers, Stormbreaker is the most powerful weapon wielded by Thor so far. The obvious reasons are that Stormbreaker is the physically larger weapon out of the two, and not to mention that it is an axe, which could well be more dangerous than a hammer.
Stormbreaker has the additional power to summon the Bifröst, allowing Thor to teleport anywhere in the Nine Realms. Screen Rant has identified Stormbreaker as the more powerful of the two, based on this ability, as well as it being a much larger and edged weapon.
Since before this Marvel “trading card” was printed Marvel has stated that Mjolnir masses 19.2 KG, or roughly 42.3 pounds. However, Mjolnir is able to, on it's own, without being held, manipulate the fundamental forces of the universe, including gravity.
Lead, tungsten, steel... we've made a lot of heavy hammers, the heaviest tipping the scales at over 140lbs! Crafting them from scratch was no easy feat, but thanks to the lessons we learned from each build, they got easier and easier to construct.
Why is Mjolnir so heavy? Mjolnir is made of Uru. It resembles stone but also has metallic properties and is able to store most energies, particularly magic. Uru is not only easy to enchant, but also absorbs magic like a sponge, redirecting it and enhancing the natural attributes of his wielder.
Unlike Mjølnir, however, the weapon is not enchanted to prevent those deemed "unworthy" from holding it, making anybody with sufficient strength capable of using the weapon.
Many viewers have pointed out that Thanos was able to lift Stormbreaker without a problem, but this is because the ax isn't enchanted as Mjolnir is. Others believe Thanos lifted Mjolnir (although briefly) and have even argued that he would be worthy of doing so.
As Thor described in Infinity War, Stormbreaker was a “Thanos-killing” weapon. Like Mjolnir, Stormbreaker is one of the most powerful weapons in the universe, and both Uru hammers nearly deal killing blows to Thanos in both Infinity War and Avengers: Endgame.
If Thor decides to use the power of lightning onboard the Asgardian refugee ship to fight the villain and his minions, he may accidentally damage the ship, or worse, even kill his own people. So, he chose to hold himself back, allowing some Asgardians to escape with Valkyrie (Tessa Thompson) and Korg (Taika Waititi).
Bill's been without Stormbreaker for a while now, as, in last year's Thor #3, Thor destroyed the powerful hammer after the pair got into a fight over his decision to join Galactus in a fight against the Black Winter.
Storm breaker is meant to be the strongest weapon of Asgard and could even summon bifrost, says Eitri. But there is no enchantment or spell on it like it was on Mjolnir. So one doesn't have to be worthy to weild it, just the strength to lift it. Clearly Thanos is capable of lifting it.
Thor's hammer Mjolnir was defined by the fact that only the 'worthy' could lift it – so basically no-one except the god of thunder (and Vision, for some reason). But when it comes to the weapon's replacement, Stormbreaker – which Thor forges in Avengers: Infinity War – Groot is able to lift it too.
The answer might be two-fold: Captain America is a super-soldier and had the strength to hold Mjolnir before. If holding Stormbreaker is a matter of simple strength, then Captain America wielding it is all the more impressive.
However, if you mean comics Thor, he can destroy planets bare handed. His powers over the storm arent dependent on a hammer. If you mean the MCU, then I would have to say yes. Eitri stated that Stormbreaker was created to surpass every weapon made before it, and Odin stated Mjolnir's power was enough to destroy worlds.
According to the official description, this amazing replica is created exactly in accordance with the size of Stormbreaker we see in the MCU films, with a 1:1 ratio. The height of the axe is 131cm/51.57inch. The text and totems are all there.
Can Magneto lift Mjolnir with his metal powers? Yes he can,, but he won't get any powers. Still though having an indestructible hammer to manipulate is pretty handy With that being said Thor can also use Mjolnir to remove Magnetos forcefields …
Notably, many of Thor's greatest feats have to do with lifting or throwing entire planets out of orbit (or objects that weigh as much as planets). He lifted the World Serpent – a creature weighing trillions of tons, using only his strength and a magic fishing rod.
The Hulk and Banner's previous conflict kept either of them from lifting Mjolnir, but their being at peace as Smart Hulk could change that. That was certainly true for the Hulk, who was shown in the first Avengers movie as being unworthy of wielding the weapon.
