I just received my 460 XVR, have not fired it yet, but I will on Saturday. I also received some Underwood 360 gr. LBT-LFN for it. I also am very pleased with the 500 mag. I will provide a range report.
Love the look of the un-fluted cylinder on that beast. Very clean. I look forward to your range report... and wish I could report on the same 2 revolvers!