Steve...I`ve an 8mm06 AI also on a 1909 Argintine,love it.
The 8x57 tho did pleasantly surprise me. Working the cartridge/rifle up to it`s potential was fun, and showed the 8 to be no slouch!
I`ve been expecting folks to suggest I`m way over pressure in arriving at these velocities, but again, no adverse pressure signs.