I've wondered about the x-die but haven't got one. I will say, I've never had an issue with any RCBS product. When I've had questions, their customer support has been awesome.
@Kib you answered your own question. The bullet had a different profile and just needs to be seated to work. Recommended COL's in manuals are just that, recommendations. You may have to seat certain bullets longer or shorter depending on your gun. There is nothing "wrong" with the Partition...
Couldn't hurt to experiment. I've used regular primers with Staball HD in the 6.5 PRC and magnums for the 7mm PRC & 7 Rem Mag. I might try mags in the 6.5 PRC just to see.
That is a handsome bullet and well cast. What mold is that? I haven't run any cast through my rifles yet, even though I have a batch of RCBS 200-FN cast up for my .35 Rem. I just need to size and load them. Only time I've ever really had any leading was from undersized bullets.
A new Marlin 1894 in .41 Mag. I'm not too picky on configuration but an octagon barrel would be sweet or a round 18" threaded barrel. Since I'm dreaming, perhaps a Springfield Waypoint with carbon fiber barrel in 6 or 25 Creedmoor.
I haven't done much testing but have used CCI, Winchester, Federal, Remington and Magtech in that order of most to least. I've never had a bad result with any. I like Federal and CCI but will get whatever is available. Dad always chose CCI's.