I used 4320 for some load development in my 7x57. I carefully worked up to the max load of 47.0 grains as shown in the Nosler data for the 120 grain Nosler BT. My groups are shown in my notes to be in the 1 to 1.5 inch range. Velocity was estimated at around 2990 to 3000 fps. These reloads were not chrono graphed. These loads were shot in a sportified Peruvian Brno manufactured Mauser M98 of the mid 1930s era with the original stepped barrel. I have since added a second 7x57 to my gun safe; a Ruger 77 Mk II. This thread has energized me to work up some more loads with the remaining 120 grain Noslers; and see if this newer rifle likes them better. But I am not holding my breath. Both the Ruger and Mausers seem to have large throats, that do not favor the lighter bullets. In my two 7x57s I seem to do better with the heavier bullets in the 150 - 175 grain weights. When I say "energized me", that is saying a lot! At age 80, it takes a bit of coaxing to get this old body to move.
!
CJ
