OK, SERIOUSLY, PECK!? It will have to have pretty high sp. attack for blizzard to be any good(and I would get ice beam anyway instead, its much more practical!). But ill Give you a few Mamoswine movesets, as ive been doing lately!
Physical Sweeper: Hail instead of Peck, and your good, he has enough health to set it up! So hail(For Blizzard), Erathquake( POWER!), Stone Edge(UNLIMITED POWER), Blizzard(plus hail, 100 acc)
Staller: Earthquake(!), Toxic(:)), light Screen(since his defenses are pretty low), and Reflect(since his defenses are pretty low).
Hope This Helps!:)