Here we take a quick look at 7mm Weatherby Magnum, an unfortunate victim of the 7mm Remington Magnum.
The 7mm Weatherby Magnum was developed in 1944 as one of a series of cartridges based on the necked-down .300 H&H case (it is the .270 WM necked up .007 inch, although it does use a longer overall cartridge length). There are several similar wildcat versions, but Weatherby’s design is the most popular, due to the availability of commercial ammunition.
The 7mm (or .284-caliber) has long been popular in the United States in various wildcat cartridges, yet the original 7mm Mauser never generated any great enthusiasm. The 7mm Weatherby Magnum, offered as a maximum-performance cartridge, is probably the best known and most widely used of the current 7mm Magnums, with the single exception of the 7mm Remington Magnum. This is due in part to the availability of factory-loaded ammunition in a good selection of bullet weights.
The 7mm Weatherby has a slight edge over the .270 Weatherby on tough or dangerous game because it can use heavier bullets and churns up greater energy. However, if long-range varmint shooting is on the agenda, the .270 is the better choice. The 7mm Weatherby Magnum is adequate for any North American big game and all thin-skinned African game. The 7mm Weatherby Magnum has, to a large extent, lost popularity to the 7mm Remington Magnum, because the Remington version is available in a wider variety of rifles that are generally less expensive than the Weatherbys.
Like most high-intensity cartridges, the 7mm WM can be somewhat hard on its barrel, especially with either careless shooting, inadequate barrel cooling between shots, or inadequate barrel cleaning. And, like all similar chamberings, it loses significant velocity with barrels shorter than 24 inches. Ammunition for this cartridge is now available from Federal and Norma, as well as Weatherby.
7mm Weatherby Magnum Loading Data and Factory Ballistics
| Bullet (grains/type) |
Powder | Grains | Velocity | Energy | Source |
| 100 HP | IMR4350 | 73.5 | 3,600 | 2,878 | Hornady |
| 115 HP | IMR4831 | 76 | 3,600 | 3,310 | Speer |
| 120 SP | IMR4350 | 70 | 3,400 | 3,081 | Sierra, Nosler, Hornady |
| 130 SP | IMR4320 | 63 | 3,300 | 3,144 | Speer |
| 139 SP | IMR4350 | 68 | 3,200 | 3,161 | Sierra, Nosler, Hornady |
| 154 SP | IMR4350 | 67 | 3,100 | 3,287 | Hornady |
| 160 SP | IMR4350 | 65 | 3,000 | 3,198 | Sierra, Speer |
| 175 SP | IMR4350 | 65 | 2,800 | 3,047 | Speer, Hornady |
| 195 SP | IMR7828 | 61 | 2,500 | 2,707 | Speer |
| 140 Barnes TSX | FL | – | 3,250 | 3,284 | Weatherby B7MM140TTSX |
| 160 Speer Trophy Bonded | FL | – | 3,100 | 3,414 | Federal P7WBTT1 |
| 170 Oryx JSP | FL | – | 2,985 | 3,364 | Norma 20171072 |
| 175 JSP | FL | – | 3,070 | 3,662 | Weatherby H7MM175SP |
Editor’s Note: This article is an excerpt of Gun Digest’s Cartridge’s Of The World.
More On Rifle Ammo:
Read the full article here