There is a 450/400 3 1/4" Nitro Express cartridge, and its ballistics are superior to the 3" by about 100fps. But the 3" is being loaded by Hornaday. Velocity of the 3" is 400gra at about 2050fps. Nominal ballistics are better, but the spec for them is from a 30" barrel.
The 450/400, either the 400 Jeffery (3") version or the 3 1/4" need to be built on the same size action as a 450NE 3 1/4". The 450/400 3 1/4" uses the same case as the 450 3 1/4". All of those can be built on a smaller action than that needed to accomodate the 500/450, 500/465, 470 (really the 500/470, or the 500, which all are based on the same case.
JPK
