The Alliant website is down right now, but they listed 2400 for the 460S&W in their 2011 reloader's guide, it's a big file at 9.62Mb, so I can't attach it.
Tim
http://www.alliantpowder.com/reloaders/default.aspx 460 S&W Mag
250 gr Speer GDHP Power Pistol Fed 210 Hornady 2.090" 21.0 1514
250 gr Speer GDHP 2400 Fed 210 Hornady 2.090" 31.0 1553
260 gr Speer HP Power Pro 300MP Fed 210 Federal 2.090˝ 36.0 1835
300 gr Speer UCSP Power Pro 300MP Fed210 Federal 2.170˝ 28.0 1610
300 gr Speer UCSP Power Pistol Fed 210 Hornady 2.170" 20.0 1359
300 gr Speer UCSP 2400 Fed 210 Hornady 2.170" 30.0 1551
300 gr Speer GDHP Power Pro 300MP Fed 210 Federal 2.150˝ 38.0 1930
300 gr Speer GDHP Power Pistol Fed 210 Hornady 2.150" 24.0 1525
300 gr Speer GDHP 2400 Fed 210 Hornady 2.150" 36.0 1782