Very interesting, thanks for sharing.
My .458/.338 Lapua Mag with 2.7" case length has about identical case capacity to your longer and skinnier .460 G&A.
I will be able to use any load data you develop, so please do pass along any loads you find particularly agreeable.
As to COL limits caused by throat length and magazine length,
I understand your pain.
I do not suffer from it myself, however.
My .458/.338 LM has a .458 WinMag throat and is built on a CZ 550 Magnum.
Can be loaded to 3.8" COL in the CZ with +3.8" mag box.
Going from 3.6" COL to 3.8" COL adds about 8.3 grains of H20 net water capacity.
That is 4.166 grains of water for each 0.1" length of shallower seating, with a .458-caliber bullet.
Why is it that so many folks cling to their tight throats ?
I am sold on the .458 WinMag throat after thousands of rounds of handloads tested in it.
The 460 Weatherby Mag throat is also way long, but of tighter diameter.
I used to shoot cloverleaf groups with that throat at 100 yards also.
Anyway, get some 404-gr Shock Hammer bullets and use them at 2500-2600 MV in your .460 G&A.
You will be able to do that at COL of 3.580" with no re-throating:
2.800" case + 0.780" nose projection, seated deep.
You will need no other bullet unless the game is heavier and thicker-skinned than a ton of cape buffalo.
But, truth be told, that load would probably be sufficient for elephant,
though an FN solid would be cricket.
