This is one of the biggest pit falls of those buying these giants without thinking!
The loading equipment for even the things like 450NE 3 1/4" requires a press with at least 4" of opening, and most case trimmers will not handle the length of most NE rounds. Now when you get a cartridge that has a diameter larger than the 500NE, the standard 7/8X14 dies are too thin in the wall to handle anything larger, and you must go to a press that has the removable threaded bushing, to aloww the large die sets for things like 577NE, 600NE and 700NE, and with enough opening to handle the length as well.
Untill RCBS came out with the AMMO Master, the length was short on just about anything available. The old RCBS BIG MAX being about your only choice over the counter. I have three presses, all RCBS, an old RCBS JR, a RCBS ROCK CHUCKER, and a RCBS BIG MAX! I use the JR for pistol loading, the rock chucker for rifle up to 375H&H, and my Nitro Express rounds on the BIG MAX.
Like someone said, when you get to the things like the 8,10,12, bore rifle cartridges, most tools are custom made, and the big 4 and 2 bore are even harder to come by, and usually come with the custom rifles if newly made, and custom made for antique rifles! Some times the loading equipment costs as much as the rifle!