458 Lott brass is pretty much unavailable at this time--I have some Hornady backordered from Midway--you can get some Hornady #8798(need to double check that #) brass and trim it down to work(getting a trimmer may be fun)--it's their basic magnum brass--no head stamp--

should be at least one crossbolt on the gun--better add another crossbolt and glass bed it--everything I've read says that after 100 or so rounds you'll have a cracked stock--

RCBS makes a trimmer, but I believe it's a custom order thing and may take 30 days to get(that's what I've found so far)

you can have Lee make you one also--probably same time frame--chris