The .375 Remington Ultra Mag
By Chuck Hawks
In 2001 Remington introduced their .375 Ultra Mag, which is based on the .300 Ultra Mag case necked up to accept .375" diameter bullets. Like the .300 Ultra Mag, this huge beltless cartridge is loosely based on the British .404 Jeffery Rimless elephant rifle case, and uses a rebated rim design to allow it to mate with standard magnum size bolt faces. The .375 Ultra requires a long magnum action. It is the largest caliber in Remington's Ultra Mag series, which also includes a .338, .300, and 7mm all on the same basic oversized case.
Remington factory loads include a 270 grain bullet at a claimed muzzle velocity (MV) of 2,900 fps and 5,041 ft. lbs. of muzzle energy (ME), and a 300 grain bullet at a MV of 2,760 fps and ME of 5073 ft. lbs. At 200 yards the 300 grain bullet is traveling at 2263 fps and retains 3412 ft. lbs. of energy. These figures were developed in a 24" test barrel.
The trajectory of the Remington 300 grain factory load looks like this: +2" at 100 yards, 0 at 200 yards, -3.5" at 250 yards, and -8.8" at 300 yards. The trajectory of both the 270 and 300 grain bullets are similar. Either is a good 250 yard heavy game load.
The reloader can approximately equal these velocities, and in addition has 235 and 250 grain bullets with which to work. Hodgdon reloading data shows that the 250 grain Barnes X-Bullet can be driven to 3090 fps with 103.0 frains of H4831 powder. The 300 grain Swift bullet can be driven to a MV of 2719 fps by 97.0 grains of H4831. These Hodgdon loads used Remington cases and primers and were tested in a 24" barrel.
These velocity figures put the .375 Ultra Mag in the same general neighborhood as the earlier .375 and .378 Weatherby Magnums. Actually, with a 300 grain bullet, the .375 Ultra is 60 fps ahead of the .375 Weatherby Magnum and only 165 fps behind the formidable .378 Weatherby Magnum.
Unfortunately, this is a neighborhood the average shooter should avoid. The recoil energy of the .375 Ultra shooting a 300 grain factory load in an 8.75 pound rifle is about 53 ft. lbs. This is substantially more severe than the recoil of a .375 H&H Magnum. In addition, it is not always easy to find a dealer that stocks .375 Ultra Mag ammunition.
For these reasons it seems unlikely that Remington's new .375 will challenge the .375 H&H Magnum's popularity. Whether it can challenge the better established .378 Weatherby Magnum remains to be seen.
What is certain is that the .375 Ultra Mag is capable of taking any animal on earth with well placed shots. Its ballistics seem more than adequate for the purposes of a .375 Magnum rifle.
Copyright 2002, 2012 by Chuck Hawks. All rights reserved.