Silvertip,
Before you go and buy a bunch of bullets, read the following. I went back thru some of my prior posts on cast bullets and my Freedom Arms 475. I cut and paste some paragraphs from those prior posts and didn't bother to edit, so some stuff may be redundant. It's all relevant and may save you some heartburn.
There is no easy answer when using cast bullets in the .475 Freedom Arms revolvers. Anything with a crimp to nose length less than or equal to .375" will fit the cyl lengthwise without having to resort to trimming the cases or seating above the crimp grove. What you have to be careful of is the diameter of the bullet in front of the crimp grove. Some of the LBT style bullets (sized to .476) will be full diameter in front of the crimp grove enough so that the bullet will not chamber in the throat even though the overall length is short enough for the cylinder. I haven't found a bullet sized to .475 that is within the overall length constraint that won't chamber in the FA.
For example, my gun likes .476 bullets, but some of the LBT style bullets sized .476 will not chamber in my gun because the forward portion of the bullet in front of the crimp groove will not enter the chamber due to tight throats. On the other hand, there are several other makes (Cast Performance & Leadheads) of bullets sized to .476 that will chamber with no problem -- diameter above crimp grove is .475, or the amount of bullet in front of the crimp grove is short enough to allow chambering.
Again, I haven't found a bullet sized to .475 that meets overall length requirements that won't chamber in the FA.
In my experience with the FA 475 LB any of the Keith SWCs with the wide front drive band above cyl throat diameter are virtually impossible to seat in tight throated cyls (they are also too long to seat normally). The LBT WFN with the longer (relative to a shorter nose in same caliber) nose to crimp measurement can also be difficult to seat. The WFNs from Cast Performance, as well as some of Leadhead’s bullets seem to be dual diameter – the base will be larger than the portion of the bullet in front of the crimp grove – so no seating problems. LFNs, and RFNs seem to be less prone to sizing/chambering problems. Unfortunately, about the only way you are going to figure it out is to actually try different nose profiles, manufacturers and diameters.
The 400gr Lee is a bit too long (.390 crimp grove to nose) to crimp normally. Using Hornady dies, I shoot/have shot a bunch of these (Lee 400gr) crimped slightly above the crimp grove using 20.0gr of 2400 without any problems. In my gun the 400gr Lee, sized .476 using 20.0gr of 2400 is a very accurate load. It runs right at 1,100 fps.
If you happen to get some bullets that won't chamber due to tight throats, you can get serviceable ammo by either crimping in front of the crimp grove, or by trimming you cases. Remember, the shorter OAL will reduce powder capacity a bit, and you will have to reduce powder charges accordingly. I'm lazy, so I crimp in front of the crimp grove. Example, the 400gr RCBS SWC, can't be crimped normally in the FA -- using 19.0gr of A2400, crimping over the front drive band chronographs about 1,160 fps at 80 deg F, while other 400gr Cast Bullets will run slightly under 1,100 fps.
The Mt Bullet Wks 400gr LBT LFNGC/PB with a nose to crimp of .370 is the longest bullet that works in my gun without trimming the cases.
With the longer bullets and heavier loads, make sure you check for crimp jump.
Ultimately, you will have to figure it out by trial and error.
Paul