Don't know where you dug up that Ruger website but this is the current one:
http://www.ruger.com/ no 375 H&Hs only Hawkeyes in 375 Ruger.
and here is what Davidson says: http://www.galleryofguns.com/genie/default.aspx?item=77RSM%2D375
NO RSMs, they aren't making them anymore. EOS
So I guess we need an autoloading 375 H&H for the uninitiated?
I'm sure Benelli could build one (GRIN) but I think they are not allowed in most African countries.
Even easier, take a 300 or 9.3x62 WinMag R-1 barrel, rebore rechamber to 375 Epstein. 76.0 Grains of IMR 4350 pushes the 270 grain Barnes X bullet at 2,597 fps average for 4,043 ft lbs of ME. Should suffice.
Lots of info on the net.
