The .270 Winchester (6.8×65mm) is an intermediate rifle cartridge, based upon the .30-06 Springfield cartridge.
History[]
The .270 Winchester was developed in 1923 by Winchester, and hit the commercial market in 1925 alongside their Winchester Model 54 bolt-action rifle.
Design details[]
The .270 Winchester is based upon the .30-06 Springfield; however, it was actually formed from the .30-03 cartridge by necking down the case to accept a .277 caliber bullet (The .270 Winchester, despite being referred to as .270 caliber (6.8mm), is actually .277 caliber (7mm)[1]). The bullet weights range from 90 grains to 160 grains, with muzzle velocity ranging from 2800 feet per second (fps) to 3600 fps, dependent upon bullet weight and barrel length.
This cartridge uses a large rifle primer, and fires with a maximum pressure of 65,000 PSI. It is best fired in a barrel with a 1:10 rifling twist.
Variants[]
The .270 Winchester comes in many different variants, mostly tailored to hunting. The bullet weights, as noted above, generally range from 90 grains to 160 grains (though some may be as much as 180 grains), and the bullets themselves may be JHP, JSP, ballistic tip, as well as other variants.