well i've been wanting to build a big bore rifle for a while now with no real luck when my dad called he found his remington hepburn action that he had lost for 20 years. not wanting it he gave it to me so whats a good big bore caliber for that type of action .i beleive it was orginally 38-55 i thought of 450-358,400 jeffery or maybe a 450 nitro express if the action would hold it