I am from AZ but will be moving to colo in Oct. I had Colo game and fish send me the regs. You cannot hunt elk in colo with a .45 cal muzzleloader it must be .50 cal or bigger for elk and moose. but you can ues a .45 for deer and antelope. You cannot use a sabot it must be a conical or round ball. you can use an inline but not use pellets. you cannot use a scope it must be open sights only. Hope this helps you out.