The late 19th century saw the development of numerous small-bore rifle cartridges. The first smokeless cartridges, such as 8mm Lebel and 8x57mm Mauser, saw a significant decrease in bullet size from the 10-11mm prevalent during the blackpowder era to .30- to .32-caliber. From there numerous militaries began to experiment with and eventually field cartridges firing bullets of 6-7mm diameter (.243”-.284”).
While some such as the 6mm Lee Navy only saw limited use, others saw significant use for decades, in particular those in the 6.5mm category. Those include the 6.5x52 Carcano, 6.5x54 Mannlicher-Schönauer, 6.5x53R Dutch Mannlicher, 6.5x50 Japanese, and the subject of this article, the 6.5x55mm Swedish Mauser.
While the 6.5x55mm is today known as the 6.5x55 Swedish Mauser, the cartridge was not actually a Mauser development. It was the result of a joint Swedish-Norwegian commission to decide on a new service cartridge to replace the 8x58R Danish Krag cartridge that was used in Swedish rolling block rifles.
Since Norway and Sweden were united under a single king but had separate armies, the two nations decided upon a common cartridge, the 6.5x55mm, while deciding to field different rifles. Norway decided on the Krag-Joergensen rifle, while Sweden decided on Mauser rifles, fielding the M1894 carbine and the M1896 rifle.
The original military loadings of the 6.5x55mm. featured a 156-grain bullet traveling at nearly 2,400 feet per second, for a muzzle energy of just under 2,000 foot-pounds. In the early 1940s Sweden adopted a spitzer cartridge featuring a 140-grain bullet traveling at 2,625 feet per second, for around 2,150 foot-pounds of muzzle energy.
While the paper ballistics of the 6.5x55m cartridge seem significantly inferior to service cartridges of other countries such as 8x57mm Mauser or .30-06 Springfield, their killing power is second to none. Because of the high sectional density of the 6.5mm bullets, they penetrate deeply and don’t need huge amounts of energy to do their damage.
The 6.5x55mm has become an incredibly popular hunting cartridge throughout Scandinavia, and with heavy bullets has even been used on big animals such as moose. With the importation of thousands of surplus Swedish military rifles to the United States, the cartridge has developed a following here too, helped by the reputation and quality of the Swedish Mauser rifles.
Because of that popularity, 6.5x55mm ammunition is relatively widely available in the United States. Some American ammunition manufacturers may use .30-06-sized (.473” head diameter) brass, whereas the 6.5x55mm needs a .480” head diameter. Use of that undersized brass can lead to case stretching or even case failure in extreme cases.
If you’re looking for a cartridge that will do it all, won’t kill your shoulder, and is readily available at sporting goods stores, you’d be hard pressed to do better than the 6.5x55 Swede.