If you're considering buying one, get a .45-70 instead.
The 45-70 can be reloaded to perform (marginally) better than the .450 due to slightly larger case capacity. Also, there is a wider range of ammunition selection for the 45-70. Right now, unless I am mistaken, there is only one factory loading available for the .450.
Also, PMC has just released a factory loading for the .45-70 that is essentially identical to the factory loading for the .450. It should be available (perhaps by order) from any gun shops and is retailing for between $22 and $26 a box.
If you've already bought one: Congratulations!
It's a fine cartridge, but the ammunition selection is a bit sparse at the moment.
Accuracy should be decent--probably 2moa or better. Trajectory isn't much to sing about--anything past 150 yards is probably pretty optimistic. Those big flat nosed bullets just don't fly very well.
