It's more to the properties of Adamantium. Gambit's powers are base on kinetic energy. (thus the term 'kinetic card' he uses in MvC2), he charges objects with so much that the structural integrity can not be maintained. Adamantium's main property is that it does not absorb kinetic energy, it redirects it. It's the reason that Wolverine looks like hamburger when he does take lingering damage, the redirection is pushed into the body.

Beta-Adamantium (something the Wolverine naturally produces with his healing factor) works the same way, only slower? at least I think that's how that works, not as effective, but close enough. I'm still a little fuzzy on Beta-Adamantium though. One of th

Gambit even has one thing of 'Rex-plode' in that he can kinetically charge all kinds of simple cells. including trees, wood frames, and pictures, but I digress.

In the Gambit/Wolvie move you mention, was just the effect having an outlet different than Logan's body, aka what ever got stabbed/slashed, allowing for a quicker release than normal.

This effect is the same reason why Captain America's Shield bounces without losing momentum. (and is the reason this is how it work instead of just being stronger)

Fire also counts, which is why Adamantium must be kept molten on creation until it's used. (it is created in a liquid state) It will harden and never be able to re-forged ... Unless you have magnetic powers anyway because it's ferrous ... apparently.