The .300 Remington Ultra Mag

By Chuck Hawks

In 1999 Remington brought out the beltless .300 Ultra Mag in their Model 700 rifle. It is loosely based on a blown out and necked down .404 Jeffery case with a 30 degree shoulder. This is a very large rimless bottleneck case.

Remington and Federal offer factory loads with 180 grain bullets (SD .271) at a muzzle velocity (MV) of 3,250 fps and muzzle energy of 4221 ft. lbs. Remington's 200 yard figures for the Nosler Partition spitzer bullet are 2834 fps and 2503 ft. lbs.

Remington also offers a 150 grain Swift Sirocco bullet (SD .226) at a MV of 3450 fps with ME of 3964 ft. lbs. The 200 yard numbers are 2980 fps and 2956 ft. lbs. This bullet seems pretty light for such a big case, but qualifies the .300 Ultra as an ultra-long range cartridge, which is probably the point of the exercise.

Here are some specifications of interest to reloaders: bullet diameter .308", maximum COL 3.600", maximum case length 2.850".

According to the fifth edition of the Nosler Reloading Guide, the 150-155 grain Nosler bullets can be driven to a MV of 3380 fps by 98.0 grains of Hodgdon's H1000 powder. A MV of 3513 fps can be achieved by a maximum load of 102.0 grains of H1000 powder.

Nosler data shows that their 180 grain bullets can be driven to a MV of 3089 fps by 92.0 grains of H1000, or a velocity of 3225 fps by a maximum load of 96.0 grains of H1000 powder. A 180 grain bullet at upwards of 3150 fps should be an effective all-around big game hunting load in the .300 Ultra Mag.

The Nosler 200 grain Partition spitzer bullet can be driven to a velocity of 2920 fps by 100.0 grains of H870 powder, or 3090 fps by a maximum load of 104.0 grains of H870 powder.

And the heavy 220 grain Partition Semi-spitzer can achieve a MV of 2828 fps when driven by 98.0 grains of H870, or a MV of 2987 fps in front of a maximum load of 102.0 grains of H870 powder. All of these Nosler loads used Remington cases and Federal 215 primers, and were tested in a 26" barrel.

Note: A full length article about the .300 Rem. Ultra Mag can be found on the Rifle Cartridge Page.

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Copyright 2004, 2012 by Chuck Hawks. All rights reserved.