Hammer,

That sounds very much like the .460 G&A, and Z-Hat's .450 UltraCat. Check out the performance of those two rounds for a pretty good idea of what a .458 RUM would be.

Another option is go with the good old .404 Jeffery.

George

The .450 Rigby and .450 Dakota are basically what you are describing. 500gr at 2475fps will get your attention.



.375 Ultra Mag Case OAL - 2.85"

Dakota .450 Case OAL - 2.9"