I' ll assume that you' ve already tried a variety of loads/bullets , have you had your bore checked ? You may just have a small burr in the barrel , or a spot where the rifling was not completely cut during manufacture . Deep cut rifling can also throw you off at first , I used to have a CVA that wouldn' t group well and it had deep cut rifling . Notice that I said used to have ... [X(] What loads/bullets have you tried so far ? I start a new rifle at minimum load and an appropriate bullet for it' s rifling then scale the powder up until I find the load that groups best in a hunting load . I generally shoot other bullets until I find one that likes the load I normally shoot . I own 2 .54s and love them , but they don' t like the same load even though the two are identical models . All part of the joys of BP shooting ! LOL