You might find that the #11 fits the "early" 7x57 case. The first rounds manufactured had a thinner rim and shallower rim cut. Later rounds had the same standardized head as all others from the same basic case. It may fit the 220 swift as well.
XXCross, Interesting info on the 7X57. I have a supply of OLD .257 brass with the thin rim and shallow extraction groove you described. Always assumed it was from a defective production run. Maybe not. Rob p.s. If anyone want's a sample, or pictures, for their collections, let me know.