.264 Winchester Magnum

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.264 Winchester Magnum
.264 Winchester Magnum
Type	Rifle
Place of origin	United States
Production history
Designer	Winchester
Designed	1959
Manufacturer	Winchester
Specifications
Case type	Rimless, bottleneck
Bullet diameter	.264 in (6.7 mm)
Neck diameter	.299 in (7.6 mm)
Shoulder diameter	.491 in (12.5 mm)
Base diameter	.515 in (13.1 mm)
Rim diameter	.532 in (13.5 mm)
Case length	2.5 in (64 mm)
Overall length	3.34 in (85 mm)
Case capacity	82 gr H2O (5.3 cm3)
Rifling twist	1:9 in (230 mm)
Primer type	Large rifle
Maximum pressure	64,000 psi (440 MPa)
Ballistic performance
Bullet mass/type Velocity Energy 100 gr (6 g) Nosler Ballistic Tip 3,510 ft/s (1,070 m/s) 2,735 ft⋅lbf (3,708 J) 125 gr (8 g) Nosler Partition 3,180 ft/s (970 m/s) 2,806 ft⋅lbf (3,804 J) 140 gr (9 g) BTSP 3,200 ft/s (980 m/s) 3,183 ft⋅lbf (4,316 J)
Test barrel length: 26 in (660 mm) Source(s): Terminal Ballistics Research[1]

The .264 Winchester Magnum is a belted, bottlenecked rifle cartridge. Except for the .244 H&H Magnum and .257 Weatherby Magnum, it is the smallest caliber factory cartridge derived from the 2.85 in (72 mm) Holland & Holland belted magnum case. It was introduced in the late 1950s and early 1960s with the .338 Winchester Magnum and the .458 Winchester Magnum as one of a family of short-cased 2.5 in (64 mm) belted magnum cartridges developed by Winchester based on the .375 Holland & Holland parent case. It was officially introduced to the public by Winchester in 1959. After many years of dwindling use it began enjoying a mild resurgence in popularity in the mid-2000s among long range rifle enthusiasts and reloaders due to the high ballistic coefficient of the heavier 6.5mm bullets and increasing popularity of cartridges such as 6.5mm Creedmoor, .260 Remington, 6.5 Grendel, benchrest and wildcat cartridges in 6.5mm.