Recently I had the opportunity to load a few hundred using both new Hornady and new Starline brass.I have both RCBS and Redding Carbide die sets. Reddings is a Titanium/Carbide set-up hmmmm... Anyway I ran into seating issues with the Hornady brass and Redding seating die. After working with Redding tech support, we discovered the Hornady case had thicker walls by around.003 to.0035. When you attempt to seat a bullet,the Redding die is to tight when the bullet enters the case and squeezes both dramatically, making it very difficult to complete and of course,unacceptable. The Starline brass works well and seats the bullet as you would expect. The RCBS die set is not as tight(precise?), and will seat either case. Using Hornady 240g XTP MAGNUM bullets, which meet spec but also varied by +/- .0005 .
Just a note on my experience on this cartridge.

I use Lee die for mine. No issues with any brass. I have found it best to crimp the bullet in a seperate operation after seating the bullet.

I have been running into similar issues reloading for my newly-acquired .460 S&W. I purchased a new "V" X frame revolver with 5 inch barrel and when attempting to resize once-fired hornady brass, I ran into all sorts of issues with cases not fitting the chambers of my revolver. I was trying not to over-work the brass but ended up not sizing it far enough down. When I went back to fully resize the brass, they still wouldn't fit in my chnmbers...

Next issue came with seating and crimping. I must have been over-crimping, as I was getting the early signs of a case wrinkle. I backed off the crimping a bit (which as Pancho suggests I do in a separate step) and I seem to be ok, however I am figuring a very heavy crimp will be needed on this big boomer.

I'm loading with a set of RCBS dies on an RCBS turret press. Brass so far has been once-fired Hornady (incidentally, I purchased it from a friend with the exact same revolver as mine, and I find it odd that I'm having such issues resizing it). I also have a bunch of new Starline brass, so as OldBrokeNeck has experienced with Hornady brass size, perhaps that's my same challenge as well. Now that I think about it, I had hell's own time trying to trim the Hornady brass on my RCBS Trim Pro. I couldn't get the .45 caliber pilot to easily enter the case and I was getting constant issues with the case pulling off the universal case holder (opposite the cutting head). I'm wondering if all of those issues are becuase the Hornady cases aren't truly .45 caliber internally and are too small for the RCBS .45 caliber pilot. I'm in for any suggestions the experts here can share!

-John