jibjab-
1- yes, cannelured bullets can be taper crimped.
2- yes. most rcbs dies for autoloaders will have, on their label, 'tc', which means taper crimp. the die seats and crimps simultaneously.
3- by 'magnums' i assume you mean 357 mag, or 480, or 454? if so, those cartridges require a roll crimp to hold the bullet in place. i suppose you could probably find dies that would tc a 357 mag, but not sure the end result is what you would want or expect.
fellas... thanks for the input... taper crimp cartridges are near-universal 'no trim', and it appears this one is split, w/ most trimming 357's... interesting, and thanks for the input.