The .7mm Weatherby Magnum is a powerful rifle cartridge supplied by Weatherby weapons in their Mark V rifles. The cartridge was one of the Weatherby company's initial cartridges. Roy Weatherby created it as part of the initial line of Weatherby cartridges in the early 1940s. The .7mm Weatherby Magnum cartridge, like the .257 Weatherby Magnum and the .270 Weatherby Magnum, is based on the.300 Holland & Holland Magnum case, necked down to .284 caliber, with a double radius neck and a straight taper. It is shortened to be fed from a standard-length action, as the.257 Weatherby Magnum and the .270 Weatherby Magnum are.
The .7mm Weatherby Magnum did not receive much attention until the early 1950s when Weatherby guns were more widely accessible. The more popular .7mm Remington Magnum, which has similar ballistics to the .7mm Weatherby Magnum, was released in 1962. Despite the fact that the .7mm Weatherby Magnum was launched 18 years earlier, it has a modest advantage over the more popular .7mm Remington Magnum in terms of ballistics due to the case design.
The .7mm Weatherby Magnum cartridge is ideal for hunting medium to large-sized animals including mule deer, wapiti, and moose. However, with properly designed bullets, the .7mm Weatherby Magnum may be utilized to hunt bigger wildlife such as great bears and American bison. It is also quite beneficial while hunting plains wildlife in Africa and Australia. It is an ultra-high velocity cartridge that provides around 300-400 fps greater velocity with lighter bullets than the more common 30-06 Springfield, which is considered to be rather fast. It's natural to cringe in anticipation of the considerable recoil.
The .28 Nosler is a shortened version of the 7mm Remington Ultra Mag. They share a maximum body diameter of 0.550 inch. Rebating the rim to 0.534 inch simplifies the production of rifle bolts since the rims of Holland & Holland-style belted magnums, such as the 7mm Remington and .300 Winchester, are the same diameter. Whereas the 7mm RUM case measures 2.387 inches long from head to body-shoulder juncture, that dimension on the .28 Nosler case is 2.166 inches.
The dimension at that point on the Nosler case is 0.002 inch larger and that reduces its body taper by just a tad. Maximum case lengths are 2.850 and 2.590 inches respectively. Shoulder angles are 30 degrees for the Remington cartridge and a slightly sharper 35 degrees for the Nosler. Due to its greater length, the Remington case is about 25 percent more capacious than the Nosler case.
The .28 Nosler case can be formed by running 7mm RUM or .300 RUM cases through a .28 Nosler full-length resizing die with its expander/decap assembly removed and then trimming to the proper length. But despite the best of efforts, case loss will be high due to wrinkling.
A case-forming die is available from Redding, and while I have not tried it, another Redding die on my shelf forms the 6.5 Remington Magnum and .350 Remington Magnum cases from the longer 7mm Remington Magnum case. Case loss is zero with it.
