Ehgr... I caught 2 shiny Beldums after a lot of effort. Took a while to merely get to 40, and then each battle took an age. Had to start with my Syncroniser, switch to Rotom to Trick Focus Sash, switch in Gengar to use Hypnosis, then Shadow Ball. From there on it was a long war of Hypnotising/Balling, all the while counting Take Downs so that it wouldn't KO itself with Struggle.
The first I had to resort to using a Master Ball, of which I have, sorry, had, two. Then it turns out that neither was Adamant. Fortunately I only saved after the first capture, but I am still 1 Master Ball dowwn and have to go through it all again.