I don't know if anyone is still reading this old post..... but here goes!

I built a .275 No.2 Magnum ( AKA 7 mm Rigby Magnum ) on a Winchester Model 70 action with a magnum bolt face back in 2006. With the use of modern steel and powders I felt safe loading it to a pressure level of approximately 52000 psi. It proved an extremely accurate rifle, and will shoot a 140 gr North Fork bullet at 2900+ fps. I took 12 animals with it ranging from vervet monkey to leopard on a safari in Zimbabwe. It has accounted for numerous deer and pronghorn in the USA. It is now my favorite light rifle for general plains hunting. The best powders in my rifle have been H4350 with the 120 gr Nosler BT & N204 with the 140 gr Barnes MRX.

Marv