i would consider the 44 magnum a big handgun round, but not a rifle..the 30-30 imo is actually to big for a handgun, but its a bigger and better concept, ya know how that went, "hey watch this"...lol..
the 44 has a way bigger projectile than a 30-30..over 100 grains in some cases...so comparing them is not an easy task, each will kill efficiently enough.