I have a friend who owns a 1972 built Auguste Francotte sidelock ejector in .458 Winchester Magnum that was regulated for Winchester Super Speed factory ammunition. Now, Winchester factory ammunition for the .458 Winchester Magnum was loaded to a velocity of 2040 FPS starting from 1969 onwards. This was not adequate for frontal brain shots on big African bull elephants. So we decided to hand load some rounds to the pre 1969 specs for Winchester’s factory loads in .458 Winchester Magnum (2130 FPS).
When we hand loaded some rounds to 2130 FPS for use in the Auguste Francotte double rifle, we were quite disheartened to see the rifle’s barrels crossfire. At 2040 FPS, we were getting tight groups out to 50 yards.
Yeah, double rifles are extremely picky eaters. Even pickier than children.