.450/400 Nitro Express

The .450/400 Nitro Express are a family of .405 - .411 caliber, rimmed, bottlenecked cases which was originally intended for black powder single shot and double rifles. There were multiple variants of each cartridge as variations existed between each manufacturer for each cartridge length. The lengths of the cartridges ranged from 3¼ inches to 2⅜ inches (82.55 mm - 60.33 mm) in case length.

Design
All cartridges were rimmed bottlenecked cartridges which were derived from various straight .450 Express cartridges. The .450 Nitro Express cartridges were necked down to accept .40 caliber (10.3 mm) bullets. Some were shortened from the original cartridges. Dimensionally there are variations between the rims of the cartridges. The cartridges which used cordite (nitros) had thicker rims to aid in the extraction of stuck cases.

Because this cartridge was conceived as a low-pressure black-powder cartridge and that several rifle manufacturers were producing rifles for this cartridge, slight variation existed between the cartridges of each manufacturers. While the bullet diameter is nominally given as .405 inches, bore as large as .411 existed. This may not have significant effects in a black-powder rifle; however, in a Nitro Express loading an undersized bullet in an oversized bore may experience accuracy issues while an oversized bullet fired in an undersized bore may cause a catastrophic failure in the firearm.

.450/400 2⅜
This case was available in three different loadings. The three loadings of this case are:
 * .450/400 2⅜ inch Black Powder Express
 * .450/400 2⅜ inch Nitro for Black Powder
 * .450/400 2⅜ inch Nitro Express

.450/400 2⅜ inch Black Powder Express
The .450/400 2⅜ inch Black Powder Express was loaded with a 210 – 270 gr. Lead bullet ahead of 79 – 84 gr. of black powder.

.450/400 2⅜ inch Nitro for Black Powder
The .450/400 2⅜ inch Nitro for Black Powder was loaded with jacketed 300 gr. round nose bullets with 40 gr. of cordite. This cartridge was meant for use in older Black Powder Express rifles.

.450/400 2⅜ inch Nitro Express
The .450/400 2⅜ inch Nitro Express was loaded with a 400 gr. RN bullet with 42 or 43 grains of cordite and was meant for use in newer rifles chambered for the .450/400 2⅜ inch case as this loading generates greater pressure than the Black Powder Express versions of the cartridge.

.450/400 3 inch
This cartridge is better known as the .400 Jeffery Nitro Express.

.450/400 3¼
The .450/400 3¼ is not a cartridge per se, but a case which can be loaded to certain specifications. The three loading of the cartridge are:
 * .450/400 3¼ inch Black Powder Express
 * .450/400 3¼ inch Nitro for Black Powder
 * .450/400 3¼ inch Nitro Express

.450/400 3¼ inch Black Powder Express
The .450/400 3¼ inch Black Powder Express was loaded with a 230 gr. - 300 gr. lead bullet backed by 110 grains of black powder. The cartridge was intended for deerstalking and usually chambered in light weight rifles. This cartridge case was intended for use in black-powder rifles.

.450/400 3¼ inch Nitro for Black Powder
The .450/400 3¼ inch Nitro for Black Powder cartridge was a cordite loaded cartridge intended for rifles which fired the .450/400 3¼ inch Black Powder Express. It was loaded with a 270 gr. - 316 gr. soft point bullet with 45 - 48 grains of cordite.

.450/400 3¼ inch Nitro Express
The .450/400 3¼ inch Nitro Express loading was intended for dangerous game. It fired a 400 gr. jacketed bullet ahead of a charge of 56 - 60 gr. of cordite at a velocity of 2150 ft/s. This cartridge is considered unsafe to use for older rifles chambered for the black powder version of this cartridge due to higher pressures generated by this loading. .450/400 3¼ inch Nitro Express rifles are heavier and were considered as the minimum cartridge necessary when hunting dangerous game.