RCBS's 147gr 9mm TMJ (totally metal jacketed) bullet has a small flat nose that wouldn't seat well with a round nose bullet seating plug, so they include the TMJ seater with the RN seater in their three die set (a pretty good deal).
If you ever have a bullet that needs a specialized seater plug, RCBS will custom-make one for you for a very reasonable fee. You just send them two samples of the bullet you want to seat and a check, and the custom seater plug will be sent to you before you know it (the bullets you send them will be returned as well). Call them before mailing so that you know how much money to send.
I've done this with a couple of bullets that I "stocked up on", and the custom seaters are a joy to use.
(I believe Lee offers this same service, but I've never used it.)