Not really, the sound stage isn't really large enough. I'm sure they aren't terrible for gaming, but if you are buying them for gaming, then it would be a poor purchase in my opinion. Many full size headphones are going to offer a superior sound stage that will be much better for gaming. They excel at what they do best, music listening.
Edit:
Didn't read the OP properly, didn't realise he already has the M50. If you already have them, then use them for gaming. No point in spending another £100+ just to get headphones that will suit positional sound better; unless positional sound is that important it's worth spending another £100. That will depend on the user I guess.