The 7mm Remington Ultra Mag
By Chuck Hawks
Remington introduced the Ultra Mag series in 1999, beginning with the .300 Ultra Mag. All of the full length Ultra Mag cartridges are based loosely on necked down British .404 Jeffery Rimless cases. All are oversize beltless magnums with rebated rim cases. The Remington Ultra Mag family includes the 7mm, .300, .338, and .375 calibers.
The 7mm Remington Ultra Mag is the smallest of the Ultra Mag calibers. It offers ballistics roughly comparable to the 7mm STW, but burns more powder to do so. Because of its great case capacity it is overbore with all but the very slowest rifle powders. And because it burns so much powder and drives bullets at very high velocity, it also burns out barrels in short order. This has done nothing for the 7mm Ultra Mag's popularity.
Remington claims that the 7mm Ultra offers a 7% flatter trajectory at 300 yards than the 7mm STW with 140 grain bullets, and comparing Remington factory loads for both calibers that is true. But Remington factory loads for the 7mm STW are among the slowest on the market. Compared to Remington 7mm Ultra Mag factory loads, A-Square 7mm STW factory loads at 3450 fps have a 25 fps advantage in MV with a 140 grain bullet. As I wrote at the beginning of this paragraph, the ballistics of the two are comparable.
By 2004 only Remington was factory loading ammunition in 7mm Ultra Mag, and the only rifle offered in the caliber is the magnum version of the Remington Model 700 bolt action. This rifle weights about 7.5 pounds (without a scope) and comes with a 26" barrel in 7mm Ultra Mag caliber.
Remington factory loads were initially offered with 140 and 160 grain bullets. Remington loaded two 140 grain bullets, a Core-Lokt PSP and a Nosler Partition spitzer. The 160 grain bullet was also a Nosler Partition spitzer. By 2004 however, due to lack of sales, this selection of factory loads had been reduced to a single offering, a 140 grain Core-Lokt Ultra at a MV of 3425 fps.
The 300 yard velocity and energy numbers for the Core-Lokt Ultra load are 2669 fps and 2214 ft. lbs. The Remington trajectory figures for that load look like this: +1.8" at 100 yards, +2.2" at 150 yards, +1.6" at 200 yards, 0 at 250 yards, -2.7" at 300 yards, and -11.9" at 400 yards. The 7mm Ultra Mag with a 140 grain bullet is among the flattest shooting cartridges on the market.
The discontinued Remington factory load with the 160 grain Nosler Partition spitzer bullet had a claimed MV of 3200 fps and a claimed ME of 3637 ft. lbs. The 300 yard figures were 2600 fps and 2401 ft. lbs. Using Remington figures, the trajectory of that load looked like this: +2.1" at 100 yards, +1.8" at 200 yards, 0 at 250 yards, -3" at 300 yards, and -12.9" at 400 yards.
The handloader has a much greater choice of bullet weights. Those lighter than 139 grains would seem pointless in such a big case, but the 150 to 175 grain bullets have their purposes. A word of caution is appropriate here: there are reports of serious powder/pressure compatability problems with the 7mm Ultra Mag and some reloading companies do not include data for the cartridge in their manuals for that reason. This is one of few calibers that could be called risky to reload. It is certainly not for the novice reloader. Follow the data in your reloading manual exactly when reloading for the 7mm Ultra Mag and do not substitute components.
According to Hodgdon reloading data the 160 grain Nosler Partition bullet can be driven to a MV of 3214 fps. The trajectory of this bullet at a MV of 3200 fps looks like this: +2.4" at 100 yards, +3" at 150 yards, +2.5" at 200 yards, and -3" at 314 yards. This is probably the best all-around bullet weight for the caliber.
Hodgdon reloading data shows a maximum MV of 3093 fps with a Swift 175 grain bullet. This is not the best bullet weight for long range shooting, but for use on very heavy game where great penetration is desirable the 175 grain bullet's sectional density of .310 makes it a viable choice.
Like most of the ultra-long range cartridges, the recoil and muzzle blast of the 7mm Ultra Mag are right up there. The Rifle Recoil Table shows that shooting a 160 grain bullet at a MV of 3200 fps in an 8.5 pound 7mm Ultra Mag rifle generates 29.4 ft. lbs. of recoil energy. Remember that above 20 ft. lbs. of recoil the average shooter may flinch badly; note that the 7mm Remington Ultra Mag delivers recoil almost 50% above the limit.
Remington advertising characterizes the 7mm Ultra Mag thusly: "Perhaps the flattest-shooting big game cartridge on the planet. Awesome choice for long-range shots on antelope, deer and sheep." A little flamboyant, perhaps, but close to the mark. What the advertising leaves out is that the standard length .240 Weatherby Magnum, .257 Weatherby Magnum, .264 Winchester Magnum, 6.5x68S, .270 Weatherby Magnum and a number of other cartridges are also excellent choices for long range shooting of the same animals and kill just as reliably with less expense, recoil, risk, and bother.
Copyright 2002, 2012 by Chuck Hawks. All rights reserved.