In collaboration with Sako Rifles, Federal Cartridge's engineers and ballistctans have developed the .338 Federal, which necks up the proven .308 Winchester case to accept a .338 caliber bullet. This design, which is the first to bear the name 'Federal' on the headstamp, is intended to provide big-bore wallop with moderate recoil for today's light weight, short bolt-action rifles. It is a commercial version of the .338-08 wildcat.

The .338 Federal bears more than a passing resemlance to the .358 Winchester cartridge, which was introduced in 1955. Like the .358 Win, the .338 Federal offers excellent performance on big game without magnum recoil. Its muzzle energy exceeds the 30-06 with a similar weight bullet. equalling the muzzle energy of the 7mm Remington Magnum. Its muzzle velocity ranges to approximately 200 feet per second greater than its parent .308 Winchester with similar weight bullets. Owners of custom .338-08 rifles should not use factory .338 Federal ammo, many custom .338-08 chambers are slightly shorter than .338 Federal cases. It is recommended that bullets larger than 225 grains because of the reduced powder capacity due to the longer bullet. Maximum pressure has been established at 62,000 psi. Maximum overall cartridge length is about 2.820'. Most powders that work for the .308 Winchester also work great for the .338 Federal. 

This text is based on information from “Cartridges of the World”, Hodgdon reloading manual, the cartridge designer and/or own resources.