Magneto flies to a place on earth where there's a 5000 ton adamantium rock, takes it to the x men secret base, has 1 hour preparation, and there's 100 sentinels coming .

Could magneto win this ?

Or could the sentinels adapt to his powers .

I think he could win because he could create himself a armor of adamantium, and use the adamantium as bullets as when he escaped from the plastic prison .

Are we talking movie or comic? Regardless, I say he can easily take one sentinel with only a fraction of that adamantium. He would have to kill it very quickly though or it would become more durable and be harder to kill.

P.s. This belongs in the Battles section, thus why no one has answered.

@bannyhaha: Thanks : p

Magneto could probably kill 90% of the heroes on Earth with that much adamantium and enough prep.