460 Rowland beats both the 10mm and the 45 and is available in a variety of kits and configurations. It is a modified 45 with a slightly longer case that is apparently strengthened...
Its in Mid 44 Magnum Power.. check out a Springfield XD Tactical with a 5 inch barrel... 13+1 Capacity and bad to the bone....
http://460rowland.com/
Buffalo Bore - 255g HC-FN 1300 FPS@957 ft lbs
Or you can look at this old thread i started complete with pics.
http://thefiringline.com/forums/show...r+in+semi+auto