The .375 2-1/2" Nitro Express (Flanged)

By Chuck Hawks

.375 2-1/2in. Nitro Express
Kynoch .375 2-1/2" NE cartridge. Illustration courtesy of Kynamco, Ltd.

The .375 2-1/2" Nitro Express is based on a flanged (British for rimmed), straight taper case. It was used in a Lee bolt action BSA magazine rifle and various single shot and double barreled rifles.

Introduced in 1899, it became moderately popular in the UK and with hunters in British colonies, but was overshadowed in 1905 by the introduction of the .375 Holland & Holland Belted and Flanged Magnums.

The .375 2-1/2" NE case is 2.50" long. The rim diameter is .523" and the head diameter is .456", tapering to a .397" neck diameter. The cartridge overall length is 3.10" and the bullet size is .375". Berdan .217" primers were used.

The original factory load offered a 270 grain RN soft point bullet (SD .274) at a muzzle velocity (MV) of 2000 fps and muzzle energy (ME) of 2400 ft. lbs. Downrange the velocity/energy looked like this:

  • 2000 fps/2400 ft. lbs at muzzle, 1735 fps/1810 ft. lbs. at 100 yards, 1405 fps/1190 ft. lbs. at 200 yards

Due to its rimmed case, the .375 2-1/2" NE was not adaptable to Mauser type bolt actions, which severely limited its popularity. It lingered on in the UK, where it had a good reputation for Red Stag and in the British African and Indian colonies, where it served primarily for Class 2 and Class 3 game. The cartridge's moderate velocity did not cause the simple soft point bullets of the pre-WW I era to fragment and the good sectional density (SD) of its 270 grain bullet gave it plenty of penetration, the key to its good performance on red stag and other large animals.

The trend toward higher velocity and the demise of the British ammo loading trust (IMI/Kynoch) in 1970 essentially made the .375 2-1/2" NE obsolete. However, Kynoch brand ammunition was reintroduced by Kynamco Limited in, I believe, the late 1990s and among the cartridges for which they now offer factory loaded ammunition is the .375 2-1/2" NE.

The current Kynoch load uses a 270 grain Woodleigh Weldcore bullet at a MV of 1975 fps and ME of 2340 ft. lbs. from a 25" barrel. This ammunition is available online from Midway USA, if you can afford it. In January 2017 a five (5) round box of Kynoch .375 2-1/2" NE cartridges was discount priced at $52.99 (not including shipping). That is $10.60 per cartridge! The only good news is that the cases are Boxer primed and reloadable.

The performance of the .375 2-1/2" NE is slightly superior to the .375 Winchester or Buffalo Bore Heavy .38-55 loads (a 255 grain bullet at 1950 fps). All of these cartridges are perfectly adequate, with proper bullets, for deer, black bear, elk, moose and even grizzly bear at woods ranges and they kick dramatically less than the .338 and .375 Magnums.

Brass for reloading the .375 2-1/2" NE is a different story, although I am told cases can be formed from .405 Winchester brass. (Also not widely available!) For contemporary North American shooters and reloaders, the .38-55 would seem to be a better bet, as both new rifles and US factory loaded ammunition are available.

Note:This article is mirrored on the Rifle Cartridges page.

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Copyright 2017 by Chuck Hawks. All rights reserved.