Denny, RCBS made 38 Special dies, they also made 357 Magnum dies (two different sets) they also made 44 Special dies and 44 Magnum dies ( two different sets), Reloaders had a bad habit, they secured the lock ring to the die, those that secured the die to the press with the lock ring used the 38 Special die to load both 357 and 38 special, same for the 44 Special, those with 44 Special dies loaded 44 Remington Magnum. Later, RCBS furnished a spacer for reloaders that could not loosen the locking nut, still, those that did not secure the lock ring to the die adjusted their dies to or off the shell holder when sizing and seating.
(Spacer for dies, goes back to the 70s)
Purchasing individual dies: Purchasing die separately is not economical, call RCBS 1 800 533 5000 to order a special order catalog.
or scroll to page 2
Page 48 list group A dies, full length sizer die is listed at about $35.00, the seating die for the same set is listed for about $30.00, The complete set of dies is listed for $42.95.