Am thinking of buying a Smith repro, Pietta of course. My question is, are the brass cases that Pietta sells worth it? I know the originals used India rubber and it's designed to expand and seal the gases in. Brass of course wouldn't do that; so is brass the way to go? Are there noticeable performance differences using a brass case? I know that Yore Supply has a urethane rubber tube they sell, and then Lodgewood makes a plastic case. Opinions? Experiences with the different kinds? Pro's vs con's?