Hello, I have a Trapdoor model 1873, ser# dates it to 1883. I am told these rifles have a 22 inch twist and were made to shoot a 405 grain bullet. I am looking to buy a mold and am trying to choose between the Lee 457-405 and Lee 459-405 HB. I also have the Trapdoor model 1884 and it is supposed to shoot 500 grain bullets. Did They change the twist to accomodate the longer, heavier bullet? I have a Lyman 500 grain mold already. Both of thes gun have bright shiney bores with excellent rifling and no I have not slugged either one. I will only be shooting BP in these guns and would appreciate any tips, Thanks, Ed