Well lets see a Hawken with that ser# should be a 1-48 twist and a 175 gr ball would be a .490 RB with a reasonably close shot that 50 cal would take an elk but you would be marginal so you would need to use a fairly stout load and place your shot behind the shoulder broadside and get both lungs, I would recommend a 110 gr load if it woud shoot accurate, 110 of RS has been the most accurate load for myself my father and my son we also use a .495 ball with a ticking [heavy ] lubed with bore butter.A maxie ball would be a better choice if they prove accurate in your gun,so would a 350 gr Power belt or sabortooth with the hollow point pluged with solder a real bullet will also some times shoot accurate in that gun. Hope this helps. Lee