The .450/400 3-1⁄4-inch NE was recreated by loading the old .450/400 3-1⁄4-inch Black Powder Express with cordite, transforming a low-velocity deerstalking cartridge into a genuine big-game hunting round capable of tackling even the largest Indian and African game.

Jeffery & Co reduced the length of the case to 3-inches and moved the neck further forward, creating this cartridge,[2] as such it was never loaded with black powder.

[3] Karamojo Bell started his elephant hunting career with a Jeffery built .450/400 double rifle prior to moving to his famous .275 Rigby.

"[6] Major Percy Powell-Cotton wrote the "Jeffery .400 ejector express rifle I first carried in my Abyssinian expedition is my favourite weapon for dangerous game.

"[6] Elmer Keith stated this cartridge would be his first choice when hunting brown bear in Alaska.