The .338-06 is simply the .30-06 case necked up. It's close to the power of a .338 Win Mag without the recoil of the magnum. Mine is a Pre-'64 Win M70 that was an '06 and it was simply rebored to .338 caliber. It's been custom stocked in French Walnut with an ebony forend tip and fleur-de-lis checkering. It shoots minute of angle with 210 Nosler Partitions at a chronographed 2810 fps. It's very effective on elk and moose with one shot kills the norm. It's my elk rifle and moose rifle when I draw a tag. Very efficient and practical cartridge is how I describe it!