I am failing to understand something about C.U.P’s. The .454 and .460 S&W brass are the same except the .460 is a little more than ¼ inch longer than the .454. Loading the .454 with Hodgdon H110 using a Hornady 240 grain XTP, the starting load is 36 grains and you have a 38,800 C.U.P. The maximum charge is 38.2 grains and the C.U.P. increases to 51,300 which is a C.U.P. increase of 12,500 with an increase of 2.2 grains of powder. Now take the 460 S&W with the same bullet, the starting load is 43.5 grains of H110 and you have a 52,200 C.U.P.
The question is why with an increase of only 2.2 grains of H110 in the .454, the C.U.P. increases 12,500, but in the .460 with an increase of 5.3 grains of H110 over the maximum load in the .454, the C.U.P. only increase 900. I would think since the brass is the same except for its length, proportionally the increase in the C.U.P should be more equal. Or another way of looking at it, if you jammed 43.5 grains in the .454 it most likely would go "ka boom" in your face but not in the .460...............
What am I missing as I try to make more sense of reloading these two rounds?
The question is why with an increase of only 2.2 grains of H110 in the .454, the C.U.P. increases 12,500, but in the .460 with an increase of 5.3 grains of H110 over the maximum load in the .454, the C.U.P. only increase 900. I would think since the brass is the same except for its length, proportionally the increase in the C.U.P should be more equal. Or another way of looking at it, if you jammed 43.5 grains in the .454 it most likely would go "ka boom" in your face but not in the .460...............
What am I missing as I try to make more sense of reloading these two rounds?
