Originally Posted by arcticap

Hornady made some .58 caliber Great Plains bullets that weigh 525 grains.
They may be discontinued and difficult to find, but The Gun Works lists them:

http://www.thegunworks.com/custprodg...Cat2Option=yes

If their fit is anything like the smaller caliber Great Plains bullets, then they'll fit tighter and be harder to load than the TC Maxi conicals.
But they will also shoot more accurately.