Substats: Crit Mutiplier&ATK&Chill, last one can be crit chance, weak point, etc.
Core: 2 chill cores, 1 magazine core, 1 fire rate core, 1 crit mutiplier core.
1 magazine core can grant u over 180 magazine, that should be quite enough, and maybe a reload mod is better if u want a magazine/reload mod. If u want more focused damage u can use weak point mods as well.
Best use with Hailey. One the one hand, hailey can siginificantly buff its crit chance, though albion cavalry has crit chance bonus on hit, but it only applies to original hit not the ricochet ones. Which is vital for quick exterminations. On the other hand, cavalry's movement speed bonus on-hit will weaken the speed debuff caused by cold fury. Crit descendants like enzo, valby could also wield it. And its high chill attrribute can be effective against darkness and immortality legion.