I'm making an OU team, that will be posted soon on the RMT, but I'm in a bit of a pickle. I don't really know what last move I should give my Mamoswine. I already have:
Definitely Ice Shard. It has so many amazing uses, from taking down opponents you have Endeavored to 1 HP, revenge killing setup Dragon type sweepers (Salamence!) and just being an amazing STAB priority attack in general. It hits hard despite its low base power thanks to his great 130 attack. Priority is almost essential for him as well, to make up for his low speed. Hope I helped! :]