I am in Canada so you are right, unless this completely stupid Order In Council is amended are better yet repealed, the 460 exceeds the 10,000 Joule limit. I can sell the gun into the States, I actually have it listed in the classifieds on here but being Left Handed the market may be a little limited. So it is sell or find a way to lower the power level below 10,000 Joules (7,500 Ft/lbs).
I did a little more research and the large difference in rim diameter would be the biggest problem, .579 vs .532 on the Lott. Fixing the bolt face would require an insert and I am not sure I want a dangerous game gun built that way. Since the barrel has express sights it would also be tricky to get it timed just right.
Easiest option is to rebarrel it to 378 Weatherby, have the barrel high gloss blued and the sights, and muzzle brake re-installed at a cost of abut $1,500. The other option I am researching is to set back the barrel and rechamber to the 460 A Square Short, which is a shortened version of the 460 Bee case with a 500 grain bullet doing about 2400 FPS.
The 450 Rigby idea has merit as well. Machinist is right, the Rim, case dimensions are a lot closer to the Bee than the Lott is.
Any other ideas are more than welcome.