They can if the gun is specifically designed for this combo (and so stamped).
How about this: A lever-action .454 Casull/.45 Colt, with a companion revolver that shoots .454 Casull, .45 Colt, or .410 shotshells - that's a versatile cowboy combo there. Can anyone knowledgable about lever actions tell me if the action will chamber either/or, with a tube full of both .454 Cas and .45 Colt? I think I've seen lever .22s that handle shorts and longs....Come to think of it I doubt this can be done even if it will cycle, because of the chamber's front edge - if you shoot a .45 Colt from a chamber for .454 Cas, the bullet could hit the chamber's edge, no? -Not a problem with a revolver.
[This message has been edited by Futo Inu (edited October 31, 1999).]