6.5x54mm Mannlicher-Schönauer

6.5x54 Mannlicher-Schönauer is a 6.55 mm (.260 cal.) rifle cartridge used in the Mannlicher-Schönauer rifle. 6.5 mm bullets are typically known for their high ballistic coefficients and sectional density, which gives them great stability in flight, resistance to wind deflection, and great penetrative power, regardless of impact velocity.

Background
Among professional elephant hunters of the 19th and 20th centuries, Walter Dalrymple Maitland Bell, who shot more than 1,000 elephants in the period 1895-1930, had a very high regard for the 6.5 Mannlicher-Schoenauer, and had Daniel Fraser of Edinburgh build him a special lightweight carbine rifle in that calibre. He only set it aside when he was unable to acquire dependable ammunition for it, and turned to a 7 x 57 mm Mauser instead. Bell's legendary name has remained closely linked with the 7 mm Mauser, but the 6.5 Mann.-Sch. was his first preference.

A modern cartridge, the 6.5mm Grendel very closely duplicates the ballistics of the 6.5 mm x 54. The American cartridge, the .257 Roberts also demonstrates many of the virtues of the 6.5 X 54. The .257 Roberts was originally designed as a wildcat cartridge by Ned Roberts, and is based on the 7 X 57 mm cartridge. Note that the 6.5 X 54 shoots a .264" bullet.

The 6.5 X 54 was referred to by the writer Ernest Hemingway as the .256 Mannlicher. Though it never replaced his favorite 30-06 Springfield, he did speak highly of it as a lion cartridge, and it was the favorite of his African guide and professional hunter Phillip Percival. The Kenya game warden and naturalist A. Blaney Percival also favored the 6.5 X 54.

In part, the 6.5 X 54's reputation stems from its use of a 160 gr bullet, giving the projectile very high sectional density and therefore penetrating ability. It requires a fast rate-of-twist rifling (about 1 in 9") to stabilize such a long bullet.